John Calvin Commentary Genesis 19:21

"And he said unto him, See, I have accepted thee concerning this thing also, that I will not overthrow the city of which thou hast spoken." — Genesis 19:21 (ASV)

See, I have accepted thee concerning this thing also. Some ignorantly argue from this expression that Lot’s prayer was pleasing to God because he assented to his request and gave him what he sought. For it is no new thing for the Lord sometimes to grant, as an indulgence, what he, nevertheless, does not approve. And he now indulges Lot, but in such a way, that he soon afterward corrects his folly.

Meanwhile, however, since God so kindly and gently bears with the evil wishes of his own people, what will he not do for us if our prayers are regulated according to the pure direction of his Spirit and are drawn from his word? But after the angel has granted him his wish respecting the place, he again reproves his indolence by exhorting him to hurry.