Genesis 18:1-15King James Version (KJV)
18 And the Lord appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day;
2 And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground,
3 And said, My Lord, if now I have found favour in thy sight, pass not away, I pray thee, from thy servant:
4 Let a little water, I pray you, be fetched, and wash your feet, and rest yourselves under the tree:
5 And I will fetch a morsel of bread, and comfort ye your hearts; after that ye shall pass on: for therefore are ye come to your servant. And they said, So do, as thou hast said.
6 And Abraham hastened into the tent unto Sarah, and said, Make ready quickly three measures of fine meal, knead it, and make cakes upon the hearth.
7 And Abraham ran unto the herd, and fetcht a calf tender and good, and gave it unto a young man; and he hasted to dress it.
8 And he took butter, and milk, and the calf which he had dressed, and set it before them; and he stood by them under the tree, and they did eat.
9 And they said unto him, Where is Sarah thy wife? And he said, Behold, in the tent.
10 And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard it in the tent door, which was behind him.
11 Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women.
12 Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also?
13 And the Lord said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old?
14 Is any thing too hard for the Lord? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son.
15 Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh.
Genesis 21:1-5King James Version (KJV)
21 And the Lord visited Sarah as he had said, and the Lord did unto Sarah as he had spoken.
2 For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him.
3 And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac.
4 And Abraham circumcised his son Isaac being eight days old, as God had commanded him.
5 And Abraham was an hundred years old, when his son Isaac was born unto him.