11 By faith also Sarah herself received strength to conceive seed and was delivered of a child when she was past age, because she judged Him who had promised to be faithful.
Hebrews 11:11 Cross References - MKJV
Genesis 17:17-19
17 And Abraham fell upon his face and laughed, and said in his heart, Shall a child be born to him that is a hundred years old? And shall Sarah, who is ninety years old, bear?
18 And Abraham said to God, Oh that Ishmael might live before You!
19 And God said, Sarah your wife shall bear you a son indeed. And you shall call his name Isaac. And I will establish My covenant with him for an everlasting covenant, and with his seed after him.
Genesis 18:11-14
11 Now Abraham and Sarah were old, far gone in days, and it had ceased to be with Sarah after the manner of women.
12 Therefore Sarah laughed within herself, saying, After my being old, shall I have pleasure, my lord being old also?
13 And Jehovah said to Abraham, Why did Sarah laugh, saying, Shall I, who am old, truly bear a child?
14 Is anything too hard for Jehovah? At the time appointed I will return again, according to the time of life, and Sarah shall have a son.
Genesis 21:1-2
Luke 1:36
36 And behold, your cousin Elizabeth also conceived a son in her old age. And this is the sixth month with her who was called barren.
Romans 4:20-21
Hebrews 10:23
23 Let us hold fast the profession of our faith without wavering (for He is faithful who promised),