Hebrews 11:11

By faith even Sarah herself received the ability to conceive [a child], even [when she was long] past the normal age for it, because she considered Him who had given her the promise to be reliable and true [to His word].

Genesis 18:11-14

Now Abraham and Sarah were old, well advanced in years; she was past [the age of] childbearing.

Hebrews 10:23

Let us seize and hold tightly the confession of our hope without wavering, for He who promised is reliable and trustworthy and faithful [to His word];

Genesis 17:17-19

Then Abraham fell on his face and laughed, and said in his heart, “Shall a child be born to a man who is a hundred years old? And shall Sarah, who is ninety years old, bear a child?”

Genesis 21:1-2

The Lord graciously remembered and visited Sarah as He had said, and the Lord did for her as He had promised.

Luke 1:36

And listen, even your relative Elizabeth has also conceived a son in her old age; and she who was called barren is now in her sixth month.

Romans 4:20-21

But he did not doubt or waver in unbelief concerning the promise of God, but he grew strong and empowered by faith, giving glory to God,

1 Peter 3:5-6

For in this way in former times the holy women, who hoped in God, used to adorn themselves, being submissive to their own husbands and adapting themselves to them;

Treasury of Scripture Knowledge

Summary

Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised.

General references

Bible References

Sara

Genesis 17:17
Then Abraham fell on his face and laughed, and said in his heart, “Shall a child be born to a man who is a hundred years old? And shall Sarah, who is ninety years old, bear a child?”
Genesis 18:11
Now Abraham and Sarah were old, well advanced in years; she was past [the age of] childbearing.
Genesis 21:1
The Lord graciously remembered and visited Sarah as He had said, and the Lord did for her as He had promised.
Luke 1:36
And listen, even your relative Elizabeth has also conceived a son in her old age; and she who was called barren is now in her sixth month.
1 Peter 3:5
For in this way in former times the holy women, who hoped in God, used to adorn themselves, being submissive to their own husbands and adapting themselves to them;

Because

Hebrews 10:23
Let us seize and hold tightly the confession of our hope without wavering, for He who promised is reliable and trustworthy and faithful [to His word];
Romans 4:20
But he did not doubt or waver in unbelief concerning the promise of God, but he grew strong and empowered by faith, giving glory to God,

General references

2 Kings 4:17
But the woman conceived and gave birth to a son at that season the next year, just as Elisha had said to her.