17 For God sent not his Son into the world, to judge the world, but that the world may be saved by him.
Theophylact: The Son of God was impassible; but being one in respect of person with man who was passable, the Son is said to be given up to death, inasmuch as He truly suffered, not in His own [Divine] nature, but in His own flesh. From this death follows an exceeding great and incomprehensible benefit.
Bede: He who by the power of His Godhead had created us to enjoy the happiness of an endless life, the same restored us to the life we have lost by taking our human frailty upon Him.
Alcuin: Truly through the Son of God shall the world have life; for no other cause came He into the world, except to save the world.
Augustine: The physician, so far as his will is concerned, heals the sick. If the sick despises or will not observe the directions of the physician, he destroys himself.
Chrysostom: Slothful men in the multitude of their sins, and excess of carelessness, abuse God’s mercy, and say, There is no hell, no punishment; God remits us all our sins. But let us remember, that there are two advents of Christ; one past, the other to come. The former was, not to judge but to pardon us: the latter will be, not to pardon but to judge us. It is of the former that He says, I have not come to judge the world [John 12:47]. Because He is merciful, instead of judgment, He grants an internal remission of all sins by baptism; and even after baptism opens to us the door of repentance, which had He not done all had been lost; for all have sinned, and come short of the glory of God [Rom 3:23].
Scripture from the Douay-Rheims Bible. Commentary from St. Thomas Aquinas, Catena Aurea, Vol. IV (London: Rivington, 1845).