But they had no child, because Elizabeth was barren, and they both were well advanced in years.
      1. What his unbelief spoke, Luke 1:18; Luke 1:18. He said to the angel, Whereby shall I know this? This was not a humble petition for the confirming of his faith, but a peevish objection against what was said to him as altogether incredible; as if he should say, "I can never be made to believe this." He could not but perceive that it was an angel that spoke to him; the message delivered, having reference to the Old-Testament prophecies, carried much of its own evidence along with it. There are many instances in the Old Testament of those that had children when they were old, yet he cannot believe that he shall have this child of promise: "For I am an old man, and my wife hath not only been all her days barren, but is now well stricken in years, and not likely ever to have children." Therefore he must have a sign given him, or he will not believe. Though the appearance of an angel, which had long been disused in the church, was sign enough,--though he had this notice given him in the temple, the place of God's oracles, where he had reason to think no evil angel would be permitted to come,--though it was given him when he was praying, and burning incense,--and though a firm belief of that great principle of religion that God has an almighty power, and with him nothing is impossible, which we ought not only to know, but to teach others, was enough to silence all objections,--yet, considering his own body and his wife's too much, unlike a son of Abraham, he staggered at the promise,Romans 4:19; Romans 4:20.