Abraham in modesty could proceed no further; and being a good man himself, he had a charitable opinion of others, and thought there certainly were so many good men in all those cities, especially including Lot and his family. No doubt Abraham remembered Lot in his prayers; but that large and generous soul could not content himself with Lot's preservation, but aims at the saving of the whole cities, which when he saw was doubtful and unlikely, he prayed for his deliverance out of that common destruction, as may be gathered from Genesis 19:29.
Related Commentaries of Genesis 18:32
Genesis 18:32
32 And he said, Oh let not the Lord be angry, and I will speak yet but this once: Peradventure ten shall be found there. And he said, I will not destroy it for ten's sake.