Genesis 19: God's announcements are rarely the last word

Two angels (not three) entered into Sodom as they intended to investigate the truth about the cries Yahweh had heard about the city (Genesis 18:21). This chapter evidences a feature of the divine that is easy to miss.

Gen 19:17-22, NRSV
When they had brought them outside, they said, “Flee for your life; do not look back or stop anywhere in the Plain; flee to the hills, or else you will be consumed.” And Lot said to them, “Oh, no, my lords; your servant has found favor with you, and you have shown me great kindness in saving my life; but I cannot flee to the hills, for fear the disaster will overtake me and I die. Look, that city is near enough to flee to, and it is a little one. Let me escape there—is it not a little one?—and my life will be saved!” He said to him, “Very well, I grant you this favor too, and will not overthrow the city of which you have spoken. Hurry, escape there, for I can do nothing until you arrive there.” Therefore the city was called Zoar.

The divine action against the cities of the valley had been determined. The judgment was going down in a determined way. Then, with Lot's input, the determined future was altered on the fly.

The God of the Bible reserves the right to alter his plans as situations change. When God announces his plans, the announcement is rarely the last word (Amos 3:6-8).