Can someone help me find a scholarly source that shows that the Old Covenant has been completely superseded and replaced by the New Covenant, so that I can show it to my friend? I tried looking in the Catholic Encyclopedia, but I didn't find much. Thanks!

The Jєωs had all the scriptures before Christ came.  It was prophecied word for word that a King not of this world come and save His people.  It is all there.  The Jєωs(scribes) did not want to accept Christ. THerefore, they continue to wait. They do not accept the new testament.  Edith Stein was a Jєω, converted to catholicism and became a nun during the time of Hitler. She read one book of St Teresa of Avila and that was all it took for her to know the truth. Edith, converted her mother. And today is the feast of Our Lady of Mount Carmel, which St. Teresa was, a carmelite.  

Can someone help me find a scholarly source that shows that the Old Covenant has been completely superseded and replaced by the New Covenant, so that I can show it to my friend? I tried looking in the Catholic Encyclopedia, but I didn't find much. Thanks!

One must understand that there is more than one "Old Covenant."  For your purposes here a discussion of the Abrahamic and Mosaic Covenants will be sufficient.

There are several articles by Dr. Sungenis here:
http://www.catholicintl.com/index.php/Jєωιѕн/covenants

The one that most suits your needs is this:
The Old Covenant: Revoked or Not Revoked?
http://www.catholicintl.com/index.php/Jєωιѕн/covenants/632-the-old-covenant-revoked-or-not-revoked

THE HEBREW BIBLE ON THE ISRAELITES—COVENANT AND JUDGMENT

In Deuteronomy 28  http://www.drbo.org/chapter/05028.htm and Leviticus 26 http://www.drbo.org/chapter/03026.htm God specified the contract of the Mosaic Covenant. He specified the duties of the Israelites to obey Him, the rewards if they obeyed Him, and the penalties if they disobeyed Him. See also: Leviticus 18:28; Numbers 14:23; Deuteronomy 4:26-27; 6:18; 7:12; Deuteronomy 30; Ezekiel 13:9; Jeremias 7:15; 29:13-14.

God did not promise to reward disobedience with power, admiration, or a real estate deal in the Middle East; He promised dispersal and misery, even to vomit them out.

Keep ye my ordinances and my judgments, and do not any of these abominations: neither any of your own nation, nor any stranger that sojourneth among you. For all these detestable things the inhabitants of the land have done, that; were before you, and have defiled it. Beware then, lest in like manner, it vomit you also out, if you do the like things, as it vomited out the nation that was before you. Every soul that shall commit any of these abominations, shall perish from the midst of his people. Keep my commandments. Do not the things which they have done, that have been before you, and be not defiled therein. I am the Lord your God. Leviticus 18:26-30
http://www.drbo.org/chapter/03018.htm

Here is God’s Judgment about how well the Israelites obeyed:

rejected Him 1 Kings 8:7
forsaken Him 1 Kings 8:8
served strange gods 1 Kings 8:8
hast not kept the commandments of the Lord 1 Kings 13:13
forsaken the commandments of God 3 Kings 18:18
mocked the messengers of God 2 Paralipomenon 36:16
despised God’s Word 2 Paralipomenon 36:16
misused the prophets 2 Paralipomenon 36:16
provoked God to wrath 2 Esdras 9:26
departed from God 2 Esdras 9:26
threw God’s law behind their backs 2 Esdras 9:26
killed the prophets, who admonished them earnestly to return to God 2 Esdras 9:26
guilty of great blasphemies 2 Esdras 9:26
forsaken the Lord Isaias 65:11
forgotten His holy mountain ( the commandments from Mt. Sinai) Isaias 65:11
didn't listen to Him Isaias 65:11
did evil Isaias 65:11
didn't answer Him Isaias 65:11
chosen the things that displease God Isaias 65:11
forsake God Jeremias 2:13
made up their own religion "that holds no water" Jeremias 2:13
had not done God's work Ezekiel 20:23
cast off His laws Ezekiel 20:23
their eyes were after the idols of their fathers Ezekiel 20:23
defiled Israel with idols Ezekiel 36:16ff
profaned His Holy Name Ezekiel 36:16ff
lying pen of the scribes wrote falsehood Jeremias 8:7ff
they all dealt deceitfully Jeremias 8:10
they voided the Covenant Jeremias 31:31-32
sacrificed to idols Jeremias 44:23
not walked in His law Jeremias 44:23
disobeyed God's commandments Jeremias 44:23
disobeyed God's Law Baruch 2:10
the people of Israel will deny the Messiah Daniel 9:25ff
no truth in Israel Osee 4:1-2
no mercy in Israel Osee 4:1-2
no knowledge of God in Israel Osee 4:1-2
sacrificed to Baalim and other idols Osee 11:2
He hates their festivities, sacrifices, and songs Amos 5:20-24
covetous in all the Israelites Amos 9:1
departed from the Law Malachias 2:8-12
made void the Covenant Malachias 2:8-12
not kept God's ways Malachias 2:8-12
despised their brothers Malachias 2:8-12
committed abominations Malachias 2:8-12
profaned the holiness of the Lord Malachias 2:8-12
married the daughter of strange gods Malachias 2:8-12

“I WILL BLESS THEM THAT BLESS THEE, AND CURSE THEM THAT CURSE THEE…”

“I will bless them that bless thee, and curse them that curse thee, and in thee shall all the kindred of the earth be blessed” Genesis 12:3
http://www.drbo.org/chapter/01012.htm

God made this covenant with Abram when he was a Gentile. There is more than one "Old" Covenant. In this context the Mosaic and Abrahamic Covenants are most germane. Judaizers intentionally conflate these Covenants to sow confusion among the faithful and to appear to elevate the ѕуηαgσgυє's damned position.

The Abrahamic Covenant was with Abram the Gentile and was a Covenant with him and his spiritual descendants.  The ѕуηαgσgυє of Satan feigns a carnal connection to Abraham, but Jesus damned that claim:
And think not to say within yourselves, We have Abraham for our father. For I tell you that God is able of these stones to raise up children to Abraham. Matthew 3:9

As you'd expect, the science and genealogy corroborate what Jesus said. The αѕнкenαzιm's origins in European Khazaria also makes the ѕуηαgσgυє's carnal "Abraham" claim laughable:

Here is an interesting paper studying mitochondrial DNA (mitochondrial DNA is inherited only from the mother, so its study is apropos their tribal obsession about who is and who is not "human" in their view). The researchers are mostly of the holy genocidal tribe (wholly genocidal tribe?):

Thomas MG, Weale ME, Jones AL, Richards M, Smith A, Redhead N, Torroni A, Scozzari R, Gratrix F, Tarekegn A, Wilson JF, Capelli C, Bradman N, Goldstein DB.
Founding mothers of Jєωιѕн communities: geographically separated Jєωιѕн groups were independently founded by very few female ancestors.
Am J Hum Genet. 2002 Jun;70(6):1411-20. Epub 2002 Apr 30.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC379128/pdf/AJHGv70p1411.pdf

Translating the distinctly technical language of their conclusion, the researchers found diversity of mitochondrial DNA slightly less than "host populations" (interesting choice of words on the researchers’ part, since "host" certainly suggests "parasite"), so they postulate several separate "founding events."  Then they note a special connection with the nation of Georgia (the former region of Khazaria).

Hence, the αѕнкenαzιs are not semitic, only slightly less diverse than "host" populations, and do have genetics suggesting a slight preponderance of "founding" mothers from the region of Khazaria.

Who cares? Notwithstanding their Master Race creed, there is no racial back door to Heaven and no racial chute to Hell.

Notwithstanding errant exegesis by Protestant dispensationalists and Zionists, God was not speaking to or about Jєωιѕн people because there was no Jєωιѕн nation—Abram, not yet Abraham, was still a Gentile and God was speaking to Abram alone.

St. Paul affirms in Galatians 3:6-8 that God’s covenant with Abram, later Abraham, was made to him as a Gentile:

“As it is written: Abraham believed God, and it was reputed to him unto justice.  Know ye therefore, that they who are of faith, the same are the children of Abraham.  And the scripture, foreseeing, that God justifieth the Gentiles by faith, told unto Abraham before: In thee shall all nations be blessed.”
http://www.drbo.org/chapter/55003.htm

St. Paul further elaborates on the justification of and covenant with Abraham before he was a Jєω in Romans chapter 4. http://www.drbo.org/chapter/52004.htm

ABRAHAMIC COVENANT WITH ALL PEOPLE IS IRREVOCABLE

Genesis 17:7 And I will establish my covenant between me and thee, and between thy seed after thee in their generations, by a perpetual covenant: to be a God to thee, and to thy seed after thee.

Hebrews 6:13-18 For God making promise to Abraham, because he had no one greater by whom he might swear, swore by himself, Saying: Unless blessing I shall bless thee, and multiplying I shall multiply thee. And so patiently enduring he obtained the promise. For men swear by one greater than themselves: and an oath for confirmation is the end of all their controversy. Wherein God, meaning more abundantly to shew to the heirs of the promise the immutability of his counsel, interposed an oath: That by two immutable things, in which it is impossible for God to lie, we may have the strongest comfort, who have fled for refuge to hold fast the hope set before us.
Galatians 3:28-29 There is neither Jєω nor Greek: there is neither bond nor free: there is neither male nor female. For you are all one in Christ Jesus. And if you be Christ's, then are you the seed of Abraham, heirs according to the promise.

MOSAIC COVENANT IS REVOKED

Through His Prophet Jeremias, God warned that He would replace the Mosaic covenant:

Jeremias 31:31-32 Behold the days shall come, saith the Lord, and I will make a new covenant with the house of Israel, and with the house of Juda: Not according to the covenant which I made with their fathers, in the day that I took them by the hand to bring them out of the land of Egypt: the covenant which they made void, and I had dominion over them, saith the Lord.

2 Corinthians 3:6-15 Who also hath made us fit ministers of the new testament, not in the letter, but in the spirit. For the letter killeth, but the spirit quickeneth. Now if the ministration of death, engraven with letters upon stones, was glorious; so that the children of Israel could not steadfastly behold the face of Moses, for the glory of his countenance, which is made void: How shall not the ministration of the spirit be rather in glory? For if the ministration of condemnation be glory, much more the ministration of justice aboundeth in glory. For even that which was glorious in this part was not glorified, by reason of the glory that excelleth. For if that which is done away was glorious, much more that which remaineth is in glory. Having therefore such hope, we use much confidence: And not as Moses put a veil upon his face, that the children of Israel might not steadfastly look on the face of that which is made void. But their senses were made dull. For, until this present day, the selfsame veil, in the reading of the old testament, remaineth not taken away (because in Christ it is made void). But even until this day, when Moses is read, the veil is upon their heart.

Colossians 2:14-15 Blotting out the handwriting of the decree that was against us, which was contrary to us. And he hath taken the same out of the way, fastening it to the cross: And despoiling the principalities and powers, he hath exposed them confidently in open shew, triumphing over them in himself.

Ephesians 2:15 Making void the law of commandments contained in decrees; that he might make the two in himself into one new man, making peace

Hebrews 7:18 There is indeed a setting aside of the former commandment, because of the weakness and unprofitableness thereof

Hebrews 8:1-13 Now of the things which we have spoken, this is the sum: We have such an high priest, who is set on the right hand of the throne of majesty in the heavens, A minister of the holies, and of the true tabernacle, which the Lord hath pitched, and not man. For every high priest is appointed to offer gifts and sacrifices: wherefore it is necessary that he also should have some thing to offer. If then he were on earth, he would not be a priest: seeing that there would be others to offer gifts according to the law, Who serve unto the example and shadow of heavenly things. As it was answered to Moses, when he was to finish the tabernacle: See (saith he) that thou make all things according to the pattern which was shewn thee on the mount. But now he hath obtained a better ministry, by how much also he is a mediator of a better testament, which is established on better promises. For if that former had been faultless, there should not indeed a place have been sought for a second. For finding fault with them, he saith: Behold, the days shall come, saith the Lord: and I will perfect unto the house of Israel, and unto the house of Juda, a new testament: Not according to the testament which I made to their fathers, on the day when I took them by the hand to lead them out of the land of Egypt: because they continued not in my testament: and I regarded them not, saith the Lord. For this is the testament which I will make to the house of Israel after those days, saith the Lord: I will give my laws into their mind, and in their heart will I write them: and I will be their God, and they shall be my people: And they shall not teach every man his neighbour and every man his brother, saying, Know the Lord: for all shall know me from the least to the greatest of them: Because I will be merciful to their iniquities, and their sins I will remember no more. Now in saying a new, he hath made the former old. And that which decayeth and groweth old, is near its end.

Hebrews 10:9 Then said I: Behold, I come to do thy will, O God: he taketh away the first, that he may establish that which followeth.


WHO ARE THE CHOSEN PEOPLE TODAY?

1 Peter 2:9-10 But you are a chosen generation, a kingly priesthood, a holy nation, a purchased people: that you may declare his virtues, who hath called you out of darkness into his marvelous light: Who in time past were not a people: but are now the people of God. Who had not obtained mercy; but now have obtained mercy.

Quote from: Capt McQuigg

Is your friend Catholic?  Trad?  Novus Ordo?  

This is the first and most important question.

Novus Ordo

Tough sell.

This whole "two covenants" stuff is just Post-Vatican II Conciliar ecuмenism on steroids - it borders on being a denial of Christ Himself!

However, ask them basics, like "Do they think Jesus is God or just sent from God?"  If they say "only sent from God" or that Our Blessed Savior only had a special relationship then I would be tempted to just say "Well, have a nice day." but let's hope it isn't the case.  

I would spend a lot of time going over the first several sentences of the Gospel of St. John and ask them line by line how they read that.  Since Jesus was with God and Jesus was God, why would a group of people who reject Him have a covenant that is still honored by the Creator?  

You want to take the approach that the Old Covenant lead to the New and wouldn't necessarily need an "end" date.  And that the Old Dispensation is strictly in preparation for the coming of the Lord and serves no other purpose, certainly not one for racial identity glorification.

Try to get them to understand that everything JP II or B XVI says isn't "handed down from Heaven" but don't overplay this or they may become defensive.

Ask them if Jesus is really God, why would He want a covenant other than His as non-revocable?  (Is that a word???)  Never to be revoked - for all time!

Ask them, philosophically, why they feel a need to defend a two-covenant system as if Jesus, Our Lord, said "No one comes to the Father except through me?"  Why would the Creator of the Old Testament and the Torah say that?

Keep us posted on how your friend responds.