St. Alphonsus says that Our Lord always gives us what we ask for in the context of spiritual goods. So in
Preparation for Death he advises to always ask Our Lord for the grace of [Final/Holy] Perseverance as well as for the grace of a great love for God. Those who do not ask for these goods are likely not to receive them.
All those who are in heaven are there for this one reason: They prayed, they asked for perseverance. All those who are in hell are there for this one reason: They did not pray and they did not ask the Lord for the grace of final perseverance.
Prayer to Obtain Final Perseverance
Eternal Father, I humbly adore and thank Thee, for having created me, and for having redeemed me. I thank Thee for having made me a Christian, by giving me the True Faith, and for adopting me as Thy child in baptism. I thank Thee for having given me time to repent, after my many sins, and for having pardoned all my offenses. I renew my sorrow for them, because I have displeased Thee. I thank Thee also for having preserved me from falling again, as I would have done, if Thou had not held me up, and saved me. But my enemies, do not cease fighting against me, nor will they, until I die. If Thou do not help me continually, I will lose Thy grace again. I, therefore, pray for perseverance till death. Thy Son Jesus, has promised that Thou will give us whatever we ask for in His Name. By the merits of Jesus Christ, I beg Thee, for myself and for all those who are in Thy grace, the grace of never more being separated from Thy Love. May we always love Thee in this life, and in the next.
Mary, Mother of God, pray to Jesus for me. So I hope. So may it be.
Amen