Talmud zu Bereschit 17:22

In which way should one honour his teacher? When the two of them walk together in the road, he should place himself on [the teacher’s] right hand and not on his left. If there be three, the Sage should be in the middle, the older man on his right and the younger on his left. For so we find it with the three Ministering Angels, Gabriel, Michael and Raphael, who came to our father Abraham. Gabriel was in the middle, Michael on his right and Raphael on his left. When they came to Abraham, the Divine Presence also came and stood above his head. He said to them, ‘Sirs, wait until I have taken leave of the Divine Presence, Who is greater than you’, as it is stated, And He left off talking with him, and God went up from Abraham.⁴Gen. 17, 22. As soon as Abraham had taken leave of the Divine Presence, he came and bowed to them, as it is stated, And when he saw them, he ran to meet them … and bowed down to the earth.⁵ibid. XVIII, 2. He led them beneath the tree and said to them, ‘Sirs, let now a little water be fetched, and wash your feet, and recline yourselves under the tree’,⁶ibid. 4. and then, I will fetch a morsel of bread and stay ye your heart.⁷ibid. 5. But what did Lot say to them? Tarry all night, and wash your feet, and ye shall rise up early, and go on your way.⁸ibid. XIX, 2. Others say: Lot surely spoke with the wisdom of the wise. If [the men of Sodom] see them with their face, hands and feet washed they would kill him and his children;⁹The people of Sodom, who were inhospitable, would kill Lot and his family for entertaining strangers. but if they see the dust on their feet [they would conclude] that they had only just arrived from their journey.