Three showed up to Abram's camp site and settled in for a conversation.
Genesis 18:
18 Now the Lord appeared to him by the oaks of Mamre, while he was sitting at the tent door in the heat of the day. 2 When he lifted up his eyes and looked, behold, three men were standing opposite him; and when he saw them, he ran from the tent door to meet them and bowed himself to the earth, 3 and said, “My Lord, ..."
Now why is it that Abraham saw three but only bowed down to and spoke to a singular?
Looking further in the chapter we see:
16 Then the men rose up from there, and looked down toward Sodom; and Abraham was walking with them to send them off. 17 The Lord said, “Shall I hide from Abraham what I am about to do,
Do you notice the use of the word "Lord" again?
And just so you can see that it is The Lord look at this part.
22 Then the men turned away from there and went toward Sodom, while Abraham was still standing before the Lord.
See the two walked off, BUT Abraham and The Lord stayed back.
23 Abraham came near and said, “Will You indeed sweep away the righteous with the wicked? 24 Suppose there are fifty righteous within the city; will You indeed sweep it away and not spare the place for the sake of the fifty righteous who are in it? 25 Far be it from You to do such a thing, to slay the righteous with the wicked, so that the righteous and the wicked are treated alike. Far be it from You! Shall not the Judge of all the earth deal justly?”
See how Abraham appeals to the Lord as the "judge of all the earth?"
26 So the Lord said, “If I find in Sodom fifty righteous within the city, then I will spare the whole place on their account.” 27 And Abraham replied, “Now behold, I have ventured to speak to the Lord, although I am but dust and ashes. 28 Suppose the fifty righteous are lacking five, will You destroy the whole city because of five?” And He said, “I will not destroy it if I find forty-five there.” 29 He spoke to Him yet again and said, “Suppose forty are found there?” And He said, “I will not do it on account of the forty.” 30 Then he said, “Oh may the Lord not be angry, and I shall speak; suppose thirty are found there?” And He said, “I will not do it if I find thirty there.” 31 And he said, “Now behold, I have ventured to speak to the Lord; suppose twenty are found there?” And He said, “I will not destroy it on account of the twenty.” 32 Then he said, “Oh may the Lord not be angry, and I shall speak only this once; suppose ten are found there?” And He said, “I will not destroy it on account of the ten.” 33 As soon as He had finished speaking to Abraham the Lord departed, and Abraham returned to his place.
Two went on to Lot's house (see the next chapter), but the Lord departed.
What is important is to notice that Christ is manifested here WITH angels but only He talks to Abraham. BUT, the angels are not part of the conversation, the conversation always takes place between Abraham and Christ.
Christ is not an angel, never was an angel. He is The Word of God made flesh. God is Spirit, but the Scriptures state, Christ took upon Himself the form of a man, and being found in the fashion of a man....
Angels do converse with even modern day believers (entertain angels unaware).
However, WE have better than angels in which we can converse with. The Lord Jesus Christ.
Though far more powerful than humankind, NO Angel died for me, and no angel can ever pay the ransom for my soul. That belongs to Christ, and He alone is to be praised.