John 6:45
“They shall all be taught of God.”
Do you see the dignity of faith, and that not of men nor by man, but by God Himself they shall learn this? And to make this assertion credible, He referred them to their prophets. “If then 'all shall be taught of God,' how is it that some shall not believe?” Because the words are spoken of the greater number. Besides, the prophecy means not absolutely all, but all that have the will. For the teacher sits ready to impart what he has to all, and pouring forth his instruction unto all.
Source: Homilies on the Gospel of John (New Advent)