Prophet Zakariya was an old, poor prophet of the Children of Israel. He worked as a carpenter to support his family. A special task Allah gave him: guarding Maryam (who would later be the mother of Prophet Isa), his niece, who was dedicated to the Bayt al-Maqdis from childhood.
Every time Zakariya came to guard Maryam in her mihrab, he saw food and out-of-season fruits. He asked: "Maryam, where is this from?" Maryam replied: "From Allah. Indeed Allah provides for whom He wills without measure."
Seeing this, Zakariya's heart stirred. He himself was very old, and his wife had been barren since youth. They had no child. But seeing the miracle in Maryam's mihrab, he became certain: if Allah can give food out of season, Allah can give a child.
Zakariya prayed quietly: "My Lord, do not leave me alone (without heir). You are the best of inheritors." (Al-Anbiya: 89)
Allah granted it. An angel came with news: "Zakariya, Allah gives glad tidings: your son Yahya will be born." Zakariya was astonished: "How? My wife is barren, and I am very old." The angel replied: "Your Lord says: 'It is easy for Me.'"
Yahya was born, who also became a prophet.
For children: a du'a for what seems impossible is still answerable — Allah loves servants who still hope when others have despaired.