Luke 1:18

And Zacharias said to the angel: According to what shall I know this? for I am old and my wife advanced in her days.

Luke 1:34

And Mary said to the angel; How shall this be, since I know not man?

Luke 1:7

And there was no child to them, as Elizabeth was barren, and both were advanced in their days.

Romans 4:19

and being not weak in faith, he considered not his body already dead, being about a hundred years old, and the deadness of Sarah's womb:

Treasury of Scripture Knowledge

Summary

And Zacharias said unto the angel, Whereby shall I know this? for I am an old man, and my wife well stricken in years.

Whereby

Bible References

Whereby

Luke 1:34
And Mary said to the angel; How shall this be, since I know not man?

For

Luke 1:7
And there was no child to them, as Elizabeth was barren, and both were advanced in their days.
Romans 4:19
and being not weak in faith, he considered not his body already dead, being about a hundred years old, and the deadness of Sarah's womb: