Zakariyya A (Zachariah) was a man of humble means, but without any hesitation, he always helped the needy. He had reached his old age without having any child.

Zakariyya A (Zachariah) was quite old but he always discharged his duty as a Messenger of Allah (God) to keep his people on His Path by constantly reminding them for it through his sermons.
He used to go to his place of worship of Allah (God) regularly despite of being very old.

Zakariyya A (Zachariah) also took care of Maryam (Mary) whose parents had dedicated for the service of the place of worship of Allah (God).

(Remember) when the wife of 'Imran said: "O my Lord! I have vowed to You what (the child that) is in my womb to be dedicated for Your services (free from all worldly work; to serve Your Place of worship), so accept this from me. Verily, You are the All-Hearer, the All-Knowing." Surah (Chapter) Al-'Imran (The Family of 'Imran) The Qur-an 3:35

Whenever Zakariyya A (Zachariah) went to his place of worship, he always visited Maryam (Mary) who used to live in a secluded room of that place of worship.
Zakariyya A (Zachariah) was always surprised to see fresh and out-of-season fruits in her room. Zakariyya A (Zachariah) knew very well that only he had access to Maryam (Mary)'s room. Upon asking about those fruits, she reminded him that Allah (God) can betow whatever He Wills on anyone whom He Wills.

So her Lord accepted her with goodly acceptance. He made her grow in a good manner and put her under the care of Zakariyya (Zachariah). Everytime he entered Al-Mihrab to visit her, he found her supplied with sustenance. He said: "O Maryam (Mary)! From where have you got this?" She said, "This is from Allah." Verily Allah provides sustenance to whom He wills, without limit. Surah (Chapter) Al-'Imran (The Family of 'Imran) The Qur-an 3:37

Zakariyya A (Zechariah) used to be very concerned that since he did not have any child, no one will continue the Mission, that Allah (God) had given him, after him. He prayed to Allah (God) for an offspring.

And remember Zakariyya (Zachariah), when he cried to his Lord: O my Lord! Leave me not single (childless), though you are the Best of the inheritors."

So We answered his call, and We bestowed upon him Yahya (John), and cured his wife (to bear a child) for him. Verily they used to call on Us with hope and fear, and used to humble themselves before Us. Surah (Chapter) Al-Anbiya (The Prophets) The Qur-an 21:89-90

Allah (God) listened to the cry of his humble and obedient servant Zakariyya A (Zechariah) and gave him the good news of a son.

(Allah said) "O Zakariyya (Zechariyah)! Verily, We give you the glad tiding of a son, whose name will be Yahya (John). We have given that name to none before (him)." Surah (Chapter) Maryam (Mary) The Qur-an 19:7

Zakariyya A (Zachariah) was left speechless by the Mercy that Allah (God) showered upon him. For a moment he could not believe the good news. He could not comprehend the news because he had grown very old and his wife was barren. He asked Allah (God) that how could that be possible? Allah (God) reminded him that it was quite easy for Him because He has all Powers.

He said: "My Lord! How can I have a son, when my wife is barren, and I have reached the extreme old age."

He said: "So (it will be). Your Lord says : It is easy for Me. Certainly I have created you before, when you had been nothing!" Surah (Chapter) Maryam (Mary) The Qur-an 19:8-9

Still confused, Zakariyya A (Zachariah) asked Allah (God) to put up a sign for him.

[Zakariyya (Zechariyah)] said: "My Lord! Appoint for me a sign." He said: "Your sign is that you shal not speak unto mankind for three nights, though having no bodily defect." Surah (Chapter) Maryam (Mary) The Qur-an 19:10

Zakariyya A (Zachariah) came out of his place of prayer and told his followers in signs to praise Allah (God).

Then he came out to his people from Al-Mihrab (a praying place or a private room) and he told them by signs to glorify Allah's praises in the morning and in the afternoon. Surah (Chapter) Maryam (Mary) The Qur-an 19:10

Allah (God) granted Zakariyya A (Zachariah) a son Yahya (John) who continued his mission of spreading the Message of Allah (God) after him.