"34. Then said Jesus, Father, forgive them; for they know not what they do. And they parted his raiment, and cast lots. 35. And the people stood beholding. And the rulers also with them derided him, saying, He saved others; let him save himself, if he be Christ, the chosen of God. 36. And the soldiers also mocked him, coming to him, and offering him vinegar, 37. And saying, If you be the king of the Jєωs, save yourself." Luke 23:34-37
"CHRYS. Because the Lord had said, Pray for them that persecute you, 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; For 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, 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 EX. 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 aloud voice proclaimed Him to be the Son of God."
http://dhspriory.org/thomas/CALuke.htm#23