The verses,

We made the iron supple for him. (34:10), and, We gave him wisdom and sound judgment in speech and decision. (38:20)

which are about David, upon him be peace, and,

We caused the fount of copper to gush forth with him. (34:12)

which is about Solomon, upon him be peace, indicate that the softening of iron is one of the greatest bounties of God, through which He shows the virtue of a great Prophet of His. Softening of iron , that is, making it soft like dough, and smelting copper, and extracting minerals is the origin and source, and basis of all material industries. So, the verses state:

Softening iron, making it like dough and fine like a thread, and smelting the copper are a great bounty granted to two great Prophets who ruled in a part of the world according to God’s commandments, and they are the means to most general industries.’ Since God endowed a Prophet who was both a Messenger and a Caliph, that is, one who was both a spiritual and worldly leader, with wise speech and craftsmanship and industry, He urges people to speak wisely and encourages them toward craftsmanship and industry.

By these ver ses, God Almighty also suggests:

O sons of Adam! I gave such wisdom to the tongue and heart of one of My servants who obeyed My religious commandments that he judged of and distinguished between all things with perfect clarity and discerned the truth. Also, I endowed him with such skill that he could cast iron into whatever mould he wished, and make use of it as an important source of strength for his rule. Since this is possible, and since iron is of great significance for, and you are in much need of it in, your social life, that wisdom and skill will be bestowed on you provided you obey My commands of creation, My laws of nature. In the course of time you will attain it!

By softening iron and smelting copper, man has achieved great progress in industry, and great power in material terms. These verses direct man’s attention towards this truth, and just as much as they warned the people of former times who did not appreciate how important it was, so too they warn those lazy people of the present.