So why was it so hard for Zachariah to believe the angel when he was told that his wife, Elizabeth was going to have a baby boy? He was a priest, surely he knew that God could do anything. He had the rope around his ankle as he went into the Holy of Holies to offer up the offering that was required of his priestly duties. He knew that anytime he was in there God could kill him. He knew the past and what God had done. Perhaps he had given up on the possibility of his wife ever getting pregnant. He chose to settle for less than what he had dreamed for so many years ago. Or did he actually doing his duties because it was his turn and not from his heart?
Obviously, Elizabeth had a little easier time in believing that anything was possible with God. After all, her husband had left for his priestly duties being able to talk and when he returned home he couldn't utter a word. Something supernatural was going on and what he acted out made much more sense than anything else. After all her sister in Club Barren, Sarah, Rachel and Hannah had all conceived and gave birth to boys when all hope was gone. Especially with Sarah being 99 years old when she gave birth. So why can't God choose to do the same to her. Finally, the curse of being barren was no longer upon her but now God had shown His favor on her.
So when you are in a circumstance that seems impossible to you what are you going to do? Are you going to give in to the hopelessness that you see all around you? Or are you going to trust in God's past record and take Him at His word?