The Appearance of God to Abraham in the Form of Three Strangers
Once, on a hot day, Abraham sat under the shadow of the oak, at the entrance of his tent, and saw Three Strangers standing before him. Abraham loved to receive strangers. He immediately got up and ran to meet Them, bowed to the earth, and invited Them to rest at his home under the tree and to strengthen Themselves with food.
The strangers came to his abode. According to the custom of that time, Abraham washed Their feet, gave Them bread which had just been prepared by his wife Sarah, set forth oil, milk, and the best fatted calf, and called Them to eat.
And They said to him, "Where is Sarah, thy wife?"
He answered, "Behold, in the tent."
One of Them said, "I will certainly return to thee in a year; and, lo, Sarah thy wife shall have a son."
Sarah, who was standing out of sight in the entrance to the tent, heard these words. She laughed to herself and thought, "How can I have such a consolation, when I am already old?"
But the Stranger said, "Wherefore did Sarah laugh?...Is anything too hard for the Lord? At the time appointed I will return unto thee,... and Sarah shall bear a son."
Then Sarah was frightened and said, "I laughed not."
But He said to her, "Nay, but thou didst laugh."
Abraham then realized that before him were not simple strangers, but that God Himself was speaking with him.
At that time Abraham was ninety-nine years old and Sarah eighty-nine.
Note: See Genesis, chap. 18:1-16.
(from: The Law of God by Fr. Seraphim Slobodskoy)