18 And Zachariah said to the angel: Whereby shall I know this? For I am an old man, and my wife is far advanced in years.
Luke 1:18 Cross References - ABU
Luke 1:7
7 And they had no child, because Elisabeth was barren; and they both were now far advanced in years.
Luke 1:34
34 Then said Mary to the angel: How shall this be, seeing that I know not a man?
Romans 4:19
19 And being not weak in faith, he considered not his own body already dead, being about a hundred years old, and the deadness of Sarah's womb.