B'resheet 18:1-2 Now the L-RD (YHWH) appeared to him by the oaks of Mamre, while he was sitting at the tent door in the heat of the day. And 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,
Abraham recognized their authority. This is another theophany of Yeshua. No one can see the father's face and live. (Ex.33:20)
John 8:56-59"Your father Abraham rejoiced to see My day, and he saw it and was glad." The Jews therefore said to Him, "You are not yet fifty years old, and have You seen Abraham?" Yeshua (Jesus) said to them, "Truly, truly, I say to you, before Abraham was born, I am." Therefore they picked up stones to throw at Him; but Yeshua (Jesus) hid Himself, and went out of the temple. NAS
The L-rd is still one.
Ephesians 4:4-8 There is one body and one Spirit, just as also you were called in one hope of your calling; one L-rd, ONE FAITH, one baptism, ONE G-D and Father of all who is over all and through all and in all. But to each one of us mercy was given according to the measure of Messiah's gift. (cf: Deut. 6:4;Mark 12:29;James 2:19)
Abraham sees the L-rd, then he sees three men. This is the foreshadowing of the tri-unity even though two of the characters may not have been divine.
It is interesting that the corresponding letter to this chapter is Tzaddi - righteous; kneeling (humility) or standing.
B'resheet 18:3-5 and said, "My L-rd, if now I have found favor in your sight, please do not pass your servant by. Please let a little water be brought and wash your feet, and rest yourselves under the tree; and I will bring a piece of bread, that you may refresh yourselves; after that you may go on, since you have visited Your servant. "And they said," So do, as you have said."
They humble themselves and willingly rest under this tree. They have a feast. This feast symbolizes a future feast, the Marriage supper of the Lamb. (Rev. 19:6-8 shown below) After this feast G-d brought judgment. This foreshadows what will happen to mankind when He returns a second time. His righteousness cannot allow mankind to continue in their downward slide.
B'resheet 18:6-8 So Abraham hurried into the tent to Sarah, and said, "Quickly, prepare three measures of fine flour, knead it, and make bread cakes. "Abraham also ran to the herd, and took a tender and choice calf, and gave it to the servant; and he hurried to prepare it. And he took curds and milk and the calf, which he had prepared, and placed it before them; and he was standing by them under the tree as they ate.
Abraham does a lot of running in this chapter. He is pretty spry for his age.
The choice calf was also reserved for people of superior rank. (cf: 1 Samuel 28:24;Luke 15:23)
Notice they were eating a meal of meat and dairy!
Revelation 19:6-10 "Hallelujah! For the L-rd our G-d, the Almighty, reigns. "Let us rejoice and be glad and give the glory to Him, for the marriage of the Lamb has come and His bride has made herself ready." And it was given to her to clothe herself in fine linen, bright and clean; for the fine linen is the righteous acts of the saints. And he said to me, "Write, 'Blessed are those who are invited to the marriage supper of the Lamb.'" And he said to me, "These are true words of G-d." And I fell at his feet to worship him. And he said to me, "Do not do that; I am a fellow servant of yours and your brethren who hold the testimony of Yeshua; worship G-d. For the testimony of Yeshua (Jesus) is the spirit of prophecy."
B'resheet 18:9-14 Then they said to him, "Where is Sarah your wife?" And he said, "Behold (look), in the tent." And He said, "I will surely return to you at this time next year; and behold, Sarah your wife shall have a son." And Sarah was listening at the tent door, which was behind him. Now Abraham and Sarah were old, advanced in age; Sarah was past childbearing. And Sarah laughed to herself, saying, "After I have become old, shall I have pleasure, my lord being old also?" And the L-RD said to Abraham, "Why did Sarah laugh, saying, 'Shall I indeed bear a child, when I am so old?' "Is anything too difficult for the L-RD?
Some things are not too difficult. There are just things He cannot do because of His righteousness. He cannot lie.
At the appointed time I will return to you, at this time next year, and Sarah shall have a son."
He states by His own authority, "SARAH WILL HAVE A SON."
What the L-rd says you can count on coming to pass!