Genesis 18:20,21 (KJV)
20 And the Lord said, Because the cry of Sodom and Gomorrah is great, and because their sin is very grievous;
21 I will go down now, and see whether they have done altogether according to the cry of it, which is come unto me; and if not, I will know.
Genesis 18:1,2 (KJV)
1 And the Lord appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day;
2 And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground,