Zechariah was a doubter.
The last time Zechariah, the Baptist's father has spoken, he had momentarily doubted God's promise that a child would be born to him and his wife in their old age. For this disbelief he was struck mute. Now, with his son's circumcision, his tongue was loosed and he used it to praise God. In a song that is often called BENEDICTUS after the first words in the Latin translation of the passage ( Luke 1, 68), Zechariah prophesied the coming of a Saviour who would redeem his people, and he predicted that his son John would prepare the Messiah's way. All the Old Testament prophecies were coming true - no wonder Zechariah praised God! The Messiah would come in Zechariah's life time, and his son had been chosen to pave the way.
Many of the people God used to accomplish great things started out as real doubters. With all of them, God showed great patience. Honest doubt was not a bad starting point as long as they didn't stay there. How great a part does doubt have in your willingness to trust God ? (Zondervan)