Here Allah tells us how He blessed His servant and Messenger Dawud (David), peace be upon him, and what He gave him of His great bounty, giving him both prophethood and kingship, and huge numbers of troops. And He blessed him with a mighty voice. Such that when he glorified Allah, the firm, solid, high mountains joined him in glorifying Allah, and the free-roaming birds, who go out in the morning and come back in the evening, stopped for him, and he was able to speak all languages. In the Sahih it is recorded that the Messenger of Allah ﷺ heard the voice of Abu Musa Al-Ash`ari, may Allah be pleased with him, reciting at night, and he stopped and listened to his recitation, then he said:
«لَقَدْ أُوتِيَ هذَا مِزْمَارًا مِنْ مَزَامِيرِ آلِ دَاوُد»
(This man has been given one of the sweet melodious voices of the Prophet Dawud.) Abu `Uthman An-Nahdi said, "I never heard any cymbal, stringed instrument or chord that was more beautiful than the voice of Abu Musa Al-Ash`ari, may Allah be pleased with him."
(Glorify) means, glorify Allah. This was the view of Ibn `Abbas, Mujahid and others. The root of this word Ta'wib means to repeat or respond, so the mountains and birds were commanded to repeat after him.
وَأَلَنَّا لَهُ الْحَدِيدَ
And We made the iron soft for him. Al-Hلasan Al-Basلri, Qata0dah, Al-A mash and others said, He did not need to heat it in the fire or beat it with a hammer؛ he could simply twist it in his hands, like a thread. Allah said:
أَنِ اعْمَلْ سَـبِغَـتٍ
Saying: Make you perfect coats of mail... , which means chain mail. Qata0dah said, He was the first person ever to make chain mail؛ before that, they used to wear plated armor.
وَقَدِّرْ فِى السَّرْدِ
(and balance well the rings of chain armor Sard,) This is how Allah taught His Prophet Dawud, peace be upon him, to make coats of mail. Mujahid said concerning the Ayah:
وَقَدِّرْ فِى السَّرْدِ
(and balance well the rings of chain armor Sard,) "Do not make the rivets too loose that the rings (of chain mail) will shake, or make them too tight that they will not be able to move at all, but make it just right." `Ali bin Abi Talhah reported that `Ibn `Abbas said, "Sard refers to a ring of iron." Some of them said, "Chain mail is called Masrud if it is held together with rivets."
and work you (men) righteousness. means, with regard to what Allah has given you of blessings.
إِنِّى بِمَا تَعْمَلُونَ بَصِيرٌ
Truly, I am All-Seer of what you do. means, watching you and seeing all that you do and say؛ nothing of that is hidden at all.