And Jehovah appeared unto him by the oaks of Mamre, as he sat in the tent door in the heat of the day. (Genesis 18:1, ASV)
The word "appeared" in this passage is a translation of the niphil form of the verb ראה (to see) and literally means "was seen," and because Yahweh can be “seen” he evidently had physical form. The text does not specifically state who was Yahweh seen by, but by context we can conclude it was Abraham.
And he lifted up his eyes and looked, and, lo, three men stood over against him: and when he saw them, he ran to meet them from the tent door, and bowed himself to the earth. (Genesis 18:2, ASV)
Abraham sees "three men." At this point we can only speculate that Yahweh was one of the three men, but the important thing here is that they are identified as "men." It should also be noted that Abraham "bowed" toward them. The Hebrew word behind "bowed" is שחה (shahhah) which literally means to prostrate oneself before another and this is the very same verb often translated as "worship." In verses 3 through 9 Abraham has a meal prepared for these men and they ask him where his wife is.
And he said, I will certainly return unto thee when the season cometh round; and, lo, Sarah thy wife shall have a son. And Sarah heard in the tent door, which was behind him. (Genesis 18:10, ASV)
One of the men informs Abraham that he will have a son, something that neither Abraham nor Sarah knew, telling us that these men have extra-ordinary power to be able to foretell the future. In verses 11 and 12 Sarah overhears the conversation and Sarah laughs.
And Jehovah said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, who am old? (Genesis 18:13, ASV)
In the context of this passage, one of the three men is speaking to Abraham about his son, and then in this verse it states that Yahweh is speaking to Abraham. Again it is still speculation that Yahweh is one of the three men, but it is looking more and more like it is. Verses 14 and 15 continue with a dialogue between Yahweh and Sarah.
And the men rose up from thence, and looked toward Sodom: and Abraham went with them to bring themon the way. (Genesis 18:16, ASV)
This verse says, "the men" rose up to leave, but it does not say specifically how many.
And Jehovah said, Shall I hide from Abraham that which I do. (Genesis 18:17, ASV)
Yahweh is now speaking to "the men." Verses 18 through 20 continue the dialogue between Yahweh and the men.
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 18:21, ASV)
Yahweh states that he is going to go to Sodom to check things out.
And the men turned from thence, and went toward Sodom: but Abraham stood yet before Jehovah. (Genesis 18:22, ASV)
This passage does not specifically state how many of the men left for Sodom. Either it was all three and Yahweh, who remains with Abraham, is not a part of three, or Yahweh is a part of the three and only two leave for Sodom. Verses 23 through 32 continue with a dialogue between Yahweh and Abraham about the number of righteous men in Sodom.
And Jehovah went his way, as soon as he had left off communing with Abraham: and Abraham returned unto his place. (Genesis 18:33, ASV)
At this point Yahweh goes on his way and Abraham returns home.
And the two angels came to Sodom at even; and Lot sat in the gate of Sodom: and Lot saw them, and rose up to meet them; and he bowed himself with his face to the earth. (Genesis 19:1, ASV)
While this translation uses “angel,” the Hebrew word is malakhiym meaning messengers. Based on the context, we can conclude that these "messengers," who have arrived at Sodom, are the very same "men" that left Abraham heading for Sodom, but notice that there are only two. This confirms that the third one was Yahweh who remained behind with Abraham. Also note that just as Abraham bowed down (worshiped) to the men when they arrived, so does Lot. Verses 2 through 10 detail the events of the two men coming to Lot's house and the incident with the men of the city.
And they smote the men that were at the door of the house with blindness, both small and great, so that they wearied themselves to find the door. (Genesis 19:11, ASV)
Again we see that these "men" are not ordinary men as we see that they have extra-ordinary power to strike the men of the city with blindness. In verses 12 through 23 the men/messengers explain to Lot what is about to happen and they work out their escape plan.
Then Jehovah rained upon Sodom and upon Gomorrah brimstone and fire from Jehovah out of heaven. (Genesis 19:24, ASV)
Back in verse 18:33, Yahweh leaves Abraham to go to Sodom, and it appears from this verse that Yahweh has arrived. But what is more interesting is that Yahweh, who appears to be standing before Sodom and Gomorrah, is raining down brimstone and fire from Yahweh who is in the sky. Two Yahwehs? More on that later. Verses 25 through 28 narrates Lot's escape from Sodom.
And it came to pass, when God destroyed the cities of the Plain, that God remembered Abraham, and sent Lot out of the midst of the overthrow, when he overthrew the cities in which Lot dwelt. (Genesis 19:29, ASV)
According to this verse Elohim sent Lot out from the city, but it was not Yahweh who sent Lot out, it was the other two messengers, who are now being identified as Elohim (plural, as in the two men/messengers).