Zakariya (Alaih Assalaam) and his wife were very old, and to their sorrow they did not have any children. They wanted very much to have a son, so Zakariya (Alaih Assalaam) prayed to Allah: Let my wife and I have a son before we die.
As Zakariya (Alaih Assalaam) was saying his prayer, an angel of Allah appeared. You have prayed to Allah and Allah has heard your prayer, the angel told him. Your wife will have a son and his name will be Yahya (Alaih Assalaam). He will be a good and honorable man and he will be Allah’s prophet.
Even though Zakariya (Alaih Assalaam) had prayed for this, he was surprised: But my wife and I are very old! He said. How can we have a son?
When Allah has willed a thing, it will happen, the angel assured him. As a sign that you are going to have a son, you must not speak to anyone for three days.

