"And as soon as He was lone, His followers along with the the twelve began asking Him about the parables. And He was saying to them, 'To you has been given the mystery of the kingdom of God; but to those who are OUTSIDE get everything in parables, IN ORDER THAT WHILE SEEING, THEY MAY SEE AND NOT PERCEIVE; AND WHILE HEARING, THEY MAY HEAR AND NOT UNDERSTAND LEST THEY RETURN AGAIN AND BE FORGIVEN."
This fact described by Jesus is why there are those humans who are among the elect (and are caused to hear and believe) and those who cannot be rescued.
Check also John 6:44, 65
Rom. 9
Acts 13:48
Eph. 1
and dozens of other passages describing the "chosen", the "elect", the "adopted".
The text leaves us with a peculiar situation...if we are called to choose Christ AND only those whom Jesus allows to come, may come, then the calls to choose Him must be subsumed by the larger picture of the God limiting the "choosing". Both "freedom to choose" and "God's choice standing" cannot be true at the same time. Mutual exclusivity, and all that. This likely does not comport with RC tradition, but the Scriptures are clear.
Amen