Марьям 19:9

Just as the creation of the first human being, without a father or a mother, was a miracle of God, the birth of a child through a father and a mother is also God’s miracle, irrespective of whether the father and mother are old or young. The fact is that it is God who creates man. He created him in the first instance and He creates man even today. The seeming cause is not the real reason, though appearances would suggest otherwise. Zachariah asked for a sign as a token of the mercy God should shower upon him. He was told that, in spite of being healthy, if he could not talk for three continuous days and nights, he should take it to be a confirmation of his wife’s pregnancy. So, when the time came, his tongue would not utter a sound and he become mute. He came out of his place of worship and started exhorting the people by signs to remember God day and night, to worship Him and always obey Him. Probably Zachariah was in the habit of delivering sermons and good advice to people every day. So when he was rendered speechless, he went to the usual meeting place and, as always, gave good advice to the people. But, since he could not speak, he counseled people by signs.