Quran

[This is a mention of the mercy of your Lord to His slave Zachariah].
Allah describes His Prophet Zachariah as His (slave) to honor him, and signify his closeness to Him. Ibn Juzay: 2/3.
Question: Allah describes His Prophet Zachariah as His (slave), why?

(When he called upon his Lord), he supplicated Him. (In private), he did it in secret because Allah hears what is hidden as well as the declared. Moreover, doing something in private is closer to sincerity and far from showing off, lest he would be blamed by others for asking Allah for a son. Ibn Juzay: 2/3.
Question: Describing the call of Zachariah as (private) indicates several things. Explain.

He prayed to Allah, expressing his weakness and incapability, and this is one of the dearest means of approaching Allah, because it is declaring one's lack of power and strength, and relying on the power and strength of Allah. Al-Saadi: 489.
Question: The story of Zachariah reveals an effective means of asking Allah. What is it?

Scholars said: It is recommended for one who supplicates Allah to mention His blessings upon him, and display submissiveness to Him as Zachariah said: (my bones have weakened). Moreover, saying: (Yet never have I been disappointed in my prayer to You, my Lord) is a mention of previous blessings from Allah by answering his supplication; meaning that whenever I supplicated You, You would always answer me. Al-Qurtubi: 13/409.
Question: What should be the demeanor of one who supplicates Allah humbly?

The reason for his fear was that he was afraid that the generation that would succeed him would be a wicked generation to the people. Thus, he asked Allah for a son who would be a Prophet after him, who would guide them with his Prophethood and what was revealed to him, so his prayer was answered. It should be noted that he was not afraid of them inheriting his wealth, for a Prophet is too great in status, and too lofty in esteem to become remorseful over his wealth in this fashion. Ibn Kathir: 3/109.
Question: Was Zachariah afraid that his inheritors would inherit his wealth after death, similar to what is done by most people today? Were the Prophets actually been inherited by others?

This glad tidings contained three things, first: Answering his supplication, which was an honor to him. Second: Granting him a son, which was adding strength to him. Third: The special name given to his son had not been given to anyone before. Al-Qurtubi: 13/417.
Question: The glad tidings that Allah gave to His Prophet Zachariah (u) contained three things. What are they?

Zachariah was astonished, and he ruled out the possibility of begetting a son while he was extremely old and his wife was barren. Nevertheless, he asked Allah for that first because he knew His power, yet he became astonished since that was a rare incident. It is said that he asked Allah when he was younger, and he was answered after he became old. Ibn Juzay: 2/4.
Question: Why did Zachariah become astonished when he received the glad tidings of a son even though he asked Allah for that?