Fatima Center quotes from The Summa/St Thomas Aquainas, on receiving the Sacraments from heretic or schismatic Priests and can be found below after this short story posted on Facebook today on St Hemenegild..
THE MARTYRDOM OF ST. HERMENEGILD
from the Dialogues of St. Gregory the Great
King Hermenegild, son of Leovigild king of the Visigoths, was converted, from the Arian heresy, to the Catholic faith, by the preaching of the venerable Leander, Bishop of Seville, one of my oldest and dearest friends. His father, who continued in the Arian heresy, did his utmost, both by promises, and threats, to induce him to apostatise. But Hermenegild returned him ever the same answer, that he never could abandon the true faith, after having once known it. The father, in a fit of displeasure, deprived him not only of his right to the throne, but of everything he possessed. And when even this failed to break the energy of his soul, he had him put into close confinement with chains on his neck and hands. Hereupon the youthful king Hermenegild began to despise the earthly, and ardently to long for the heavenly, kingdom. Thus fettered, and wearing a hairshirt, he besought the Omnipotent God to support him. As to the glory of this fleeting world, he nobly looked on it with disdain, the more so as his captivity taught him the nothingness of that which could thus be taken from him.
It was the Feast of Easter. At an early hour of the night, when all was still, his wicked father sent an Arian Bishop to him, with this message, that if he would receive Communion from his hands, (the Communion of a sacrilegious consecration!) he should be restored to favour. True to his Creator, the man of God gave a merited reproof to the Arian Bishop, and, with holy indignation, rejected his sinful offer; for though his body lay prostrate in chains, his soul stood on ground beyond the reach of tyranny. The Bishop therefore, returned whence he had come. The Arian father raged, and straightway sent his lictors, bidding them repair to the prison of the unflinching Confessor of the Lord, and murder him on the spot. They obeyed; they entered the prison; they cleft his skull with a sword; they took away the life of the body, and slew what he, the slain one, had sworn to count as vile. Miracles soon followed, whereby heaven testified to the true glory of Hermenegild; for during the night, there was heard sweet music nigh to the body of the King and Martyr,--King indeed, because he was a Martyr.
It is said that lights were seen at the same time burning in the prison. The Faithful were led, by these signs, to revere the body, as being that of a martyr. As to the wicked father, he repented for having imbrued his hands in his son's blood; but his repentance was not unto salvation, inasmuch as, whilst acknowledging the Catholic Faith to be the true one, he had not the courage to embrace it, for he feared the displeasure of his subjects. When in his last sickness, and at the point of death, he commended his son Reccared, a heretic, to the care of Leander the Bishop, whom he had hitherto persecuted, but from whom he now asked, that he would do for this son what he had, by his exhortations, done for Hermenegild. Having made this request, he died, and was succeeded on the throne by Reccared, who taking, not his wicked father, but his martyred brother, as his model, he abandoned the impious Arian heresy, and led the whole Visigoth nation to the true Faith. He would not allow any man to serve in his armies, who dared to continue the enemy of the God of hosts by heresy. Neither is it to be wondered at, that being the brother of a Martyr, he should have become a propagator of the true Faith, for it was by Hermenegild's merits that he has succeeded in reconciling so many thousands to the great God of heaven.
# THE WITNESS OF ST. HERMENEGILD
to an All-But Lost Dogma of Faith in Our Time:
Outside of the Church There Is No Salvation
by Dom Prosper Gueranger
Hermenegild, a young Visigoth Prince, is put to death by his heretical father, because he courageously refused to receive his Easter Communion from an Arian Bishop. The Martyr knew that the Eucharist is the sacred symbol of Catholic unity; and that we are not allowed to approach the Holy Table in company with them that are not in the true Church. A sacrilegious consecration gives heretics the real possession of the Divine Mystery, if the priestly character be in him who dares to offer Sacrifice to the God whom he blasphemes; but the Catholic, who knows that he may not so much as pray with heretics, shudders at the sight of the profanation, and would rather die than share, by his presence, in insulting our Redeemer in that very Sacrifice and Sacrament, which were instituted that we might all be made one in God.
The blood of the Martyr produced its fruit: Spain threw off the chains of heresy that had enslaved her, and a Council, held at Toledo, completed the work of conversion begun by Hermenegild's sacrifice. There are very few instances recorded in history of a whole Nation rising up in a mass to abjure heresy; but Spain did it. Shortly after this she was put through the ordeal of the Saracen invasion; she triumphed here again by the bravery of her children; and ever since then, her Faith has been so staunch and so pure, as to merit for her the proud title of The Catholic Kingdom.
# ST. THOMAS AQUINAS ON ST. HERMENEGILD’S EXAMPLE
Summa Theologica, Part III, Q. 82, A. 9
Whether it is permissible to receive communion from heretical, excommunicate, or sinful priests, and to hear mass said by them?
On the contrary, Gregory says (Dial. ii.) that "the faithless father sent an Arian bishop to his son, for him to receive sacrilegiously the consecrated Communion at his hands. But when the Arian bishop arrived, God's devoted servant rebuked him, as was right for him to do."
I answer that heretical, schismatical, excommunicate, or even sinful priests, although they have the power to consecrate the Eucharist, yet they do not make a proper use of that power; on the contrary, they sin by using it. But whoever communicates with another who is in sin, becomes a sharer in his sin. Hence we read in John's Second Epistle (11) that "He that saith unto him, God speed you, communicateth with his wicked works." Consequently, it is not lawful to receive Communion from them, or to assist at their Mass.
The unity of the mystical body is the fruit of the true body received. But those who receive or minister unworthily, are deprived of the fruit. And therefore, those who belong to the unity of the Faith are not to receive the sacrament from their dispensing.
By refusing to hear the masses of such priests, or to receive Communion from them, we are not shunning God's sacraments; on the contrary, by so doing we are giving them honor (hence a host consecrated by such priests is to be adored, and if it be reserved, it can be consumed by a lawful priest): but what we shun is the sin of the unworthy ministers.