5 And not merely in works, but also in faith, has God preserved the will of man free and under his own control, saying, “According to your faith be it unto you;” thus showing that there is a faith specially belonging to man, since he has an opinion specially his own. And again, “All things are possible to him that believes;” and, “Go your way; and as you have believed, so be it done unto you.” Now all such expressions demonstrate that man is in his own power with respect to faith. And for this reason, “he that believes in Him has eternal life while he who believes not the Son has not eternal life, but the wrath of God shall remain upon him.” In the same manner therefore the Lord, both showing His own goodness, and indicating that man is in his own free will and his own power, said to Jerusalem, “How often have I wished to gather your children together, as a hen [gathers] her chickens under her wings, and you would not! Wherefore your house shall be left unto you desolate.”
Source: Adversus haereses (New Advent)