John Calvin Commentary Genesis 19:17

"And it came to pass, when they had brought them forth abroad, that he said, Escape for thy life; look not behind thee, neither stay thou in all the Plain; escape to the mountain, lest thou be consumed." — Genesis 19:17 (ASV)

Escape for your life. This was added by Moses to teach us that the Lord not only stretches out his hand to us for a moment to begin our salvation, but that without leaving his work imperfect, he will carry it on even to the end. It certainly was no common act of grace that the ruin of Sodom was predicted to Lot himself, lest it should crush him unawares; next, that a certain hope of salvation was given him by the angels; and finally, that he was led by the hand out of the danger.

Yet the Lord, not satisfied with having granted him so many favors, informs him of what was afterwards to be done, and thus proves himself to be the Director of his course until he should arrive at the haven of safety. Lot is forbidden to look behind him, so that he may know that he is leaving a pestilential habitation.

This was done, first, so that he might not indulge any desire for it, and then, so that he might better reflect on the singular kindness of God, by which he had escaped hell.

Moses had previously related how fertile and rich that plain was; Lot is now commanded to depart from there, so that he may perceive himself to have been delivered, as if from the midst of a shipwreck.

And although, while dwelling in Sodom, his heart was continually vexed; it was still scarcely possible for him to avoid contracting some defilement from such a profound sink of wickedness. Now, therefore, being about to be purified by the Lord, he is deprived of those delights in which he had taken too much pleasure.

Let us also learn from this that God best provides for our salvation when he cuts off those superfluities which serve for pampering the flesh, and when, to correct excessive self-indulgence, he banishes us from a sweet and pleasant plain to a desert mountain.