The words are much the same with those of Abraham, Genesis 15:8, Whereby shall I know that I shall inherit it, viz. the land of Canaan? And Mary, Luke 1:34, when the same angel had told her she should have a child, Luke 1:31, saith, How shall this be, seeing I know not a man? Gideon also asked a sign, Judges 6:17. To our appearance and judgment there seemeth no great difference betwixt these and Zacharias in this place asking a sign, only Zacharias here opposeth his own sense and reason to the words of the angel, yet we shall hear a different issue of this question, or answer to it.
Related Commentaries of Luke 1:18
Luke 1:18
18 And Zacharias said unto the angel, Whereby shall I know this? for I am an old man, and my wife well stricken in years.