Abraham looked up and saw three men standing nearby. When he saw them, he hurried from the entrance of his tent to meet them and bowed low to the ground.
Genesis 18:2 (NIV)
In Genesis 18, we have this odd story about three men who meet Abraham. We’ll learn that they are angels, as two of them continue on to destroy the cities of Sodom and Gomorrah in the next chapter.
The Rabbis ask, “Why THREE angels? Couldn’t one angel have done it all?”
In response, they suggest that perhaps an angel can only carry out one mission:
One to make an announcement
One to overthrow the cities of Sodom and Gomorrah
One to cure Abraham after his circumcision
והנה שלשה אנשים AND BEHOLD THREE MEN — one to announce to Sarah the birth of a son, one to overthrow Sodom, and one to cure Abraham, for one angel does not carry out two commissions.
Rashi on Genesis 18:1:1a
This may sound farfetched, but they have a reason for this. If you read through Genesis 18 and 19, the men switch between answering in the plural and in the singular at different times in the chapter.
You may know that this is so because throughout this section it (Scripture) mentions them in the plural — “and they ate” (Genesis 18:8), “and they said unto him” (Genesis 18:9) — whilst in the case of the announcement it states, (Genesis 18:10) “And he said, I will certainly return unto thee”, and with regard to the overthrow of Sodom it says (Genesis 19:22) “For “I” cannot do anything” and (Genesis 19:21) “that “I” will not overthrow [the city]”. Raphael who healed Abraham went thence to rescue Lot; that explains what is stated (Genesis 19:17) “And it came to pass when they had brought them forth, that he said, Escape for thy life”, for you learn from this that only one of these acted as Deliverer.
Rashi on Genesis 18:1:1b
While that’s all very interesting, the most challenging thing about the chapter is that the men also appear to be interchangeable with God. Sometimes Abraham is speaking to the angels, and sometimes the text says he is speaking to God.
When the men got up to leave, they looked down toward Sodom, and Abraham walked along with them to see them on their way. Then the Lord said, “Shall I hide from Abraham what I am about to do?
Genesis 18:16-17 (NIV)
There’s no concensus here. It’s a mystery. But it’s from this chapter that the notion of some kind of triune nature of God first shows up in the text. Not in the “Father/Son/Holy-Spirit” kind of way, but at least something that shows that God is more complex than we realize.