“And the birds” is coordinated with the syntactic position of “the mountains,” since every vocative occupies the accusative position. It is also said to mean: We subjected the birds and commanded them to glorify Allah with him. Ya'qub recited it in the nominative: “and the birds,” coordinated with “the mountains”—that is, “Echo praises, you mountains and the birds.” Whenever David called out in a place, the mountains answered him with their echo, while the birds gathered above him. Thus, the echoes of the mountains that people hear today stem from that.

It is also said that whenever David passed through the mountains and glorified Allah, the mountains would answer him with glorification similar to his own.

It is further said that whenever David, peace be upon him, was overcome by weariness, Allah would let him hear the glorification of the mountains in order to invigorate him. (1)

“And We made iron pliant for him”: so that ⦗87/a⦘ iron became in his hand like wax and dough, and he could make from it whatever he wished without fire or the striking of a hammer.

According to what is related in the reports, the reason for this was that, when David, peace be upon him, became king over the Children of Israel, it was his custom to go out among the people in disguise. Whenever he saw a man who did not know him, he would approach him and ask about David, saying, “What do you say about this governor of yours, David? What kind of man is he?” They would praise him and speak well of him. Then Allah sent him an angel in the form of a human being. When David saw him, he approached him as was his custom and asked him. The angel replied, “He is an excellent man, were it not for one quality in him.” This alarmed David, and he said, “What is it, servant of Allah?” He replied, “He eats and feeds his dependents from the public treasury.”

David then took note of this and asked Allah to grant him a means through which he could be independent of the public treasury, from which he could earn his livelihood and feed his dependents. Allah, exalted is He, therefore made iron pliant for him and taught him the craft of making coats of mail; and he was the first to make them. (2) It is said that he sold each coat of mail for four thousand dirhams, from which he ate, fed his dependents, and gave charity to the poor and needy.

It is also said that he made one coat of mail each day and sold it for six thousand dirhams. He would spend two thousand of it on himself and his dependents, and give four thousand in charity to the poor among the Children of Israel. (3) The Messenger of Allah, may Allah bless him and grant him peace, said: “David, peace be upon him, ate only from the work of his own hand.” (4)

“Make full coats of mail, and measure well the links; and do righteous deeds. Indeed, I see all that you do.” (11)

“Make full coats of mail”: that is, complete, broad, and long coats of mail that trail upon the ground. “And measure well the links”: sard means the weaving of coats of mail; its maker is called a sarrad or zarrad—that is, a maker of mail. He means: proportion the rivets in the links of the coat of mail.