Genesis 18:31-33 meaning

Abraham continues his intercession, now in increments of ten.  After starting the bargaining at fifty, Abraham gets down to twenty, then decides to make one final ask. "Suppose ten are found there?" (v 32). Interestingly, ten was the number in Lot's family. There were Lot and his wife, two sons, two married daughters, two son-in-law's, and two unmarried daughters (Genesis 19:12-14). God promises, "I will not destroy it on account of the ten" (v 32). We will soon learn, Lot must leave Sodom, so that God can punish the wicked (Genesis 19:16-17).

When the conversation between God and Abraham ended, the Lord departed and Abraham returned to his place (v 33), his tent by the Oaks of Mamre at Hebron (Genesis 13:18, 18:1). The events of this chapter took place in one afternoon at Mamre.