Father forgive them. What does Jesus mean in saying that?

 Catena Aurea

34. Then said Jesus, Father, forgive them; for they know not what they do. 

CHRYSOSTOM. Because the Lord had said, Pray for them that persecute you, (Matt. 5:44.) this likewise He did, when He ascended the cross, as it follows, Then said Jesus, Father, forgive them, not that He was not able Himself to pardon them, but that He might teach us to pray for our persecutors, not only in word, but in deed also. But He says, Forgive them, if they should repent. For He is gracious to the penitent, if they are willing after so great wickedness to wash away their guilt by faith.

BEDE. Nor must we imagine here that He prayed in vain, but that in those who believed after His passion He obtained the fruit of His prayers? It must be remarked, however, that He prayed not for those who chose rather to crucify, rather than to confess Him whom they knew to be the Son of God, but for such as were ignorant what they did, having a zeal for God, but not according to knowledge, as He adds, For they know not what they do.

GREEK EXPOSITOR. But for those who after the crucifixion remain in unbelief, no one can suppose that they are excused by ignorance, because of the notable miracles that with a loud voice proclaimed Him to be the Son of God.

Denzinger Sources of Catholic Dogma

COUNCIL OF SENS * 1140 or 1141

The Errors of Peter Abelard *

377 10. That they have not sinned who being ignorant have crucified Christ, and that whatever is done through ignorance must not be considered as sin.

Various Errors on Moral Subjects (II) * 

[Condemned in a decree of the Holy Office, March 4, 1679] 


1154  4. An infidel who does not believe will be excused of infidelity, since  he is guided by a less probable opinion.