Though he heap up silver as the dust - That is, in great quantities - as plenty as dust; compare 1 Kings 10:27, "And the king made silver to be in Jerusalem as stones."

And prepare raiment - Oriental wealth consisted much in changes of raiment. Sir John Chardin says that in the East it is common to gather together immense quantities of furniture and clothes. According to D'Herbelot, Bokteri, an illustrious poet; of Cufah in the ninth century, had so many presents made him in the course of his life, that when he died he was found possessed of an hundred complete suits of clothes, two hundred shirts, and five hundred turbans. compare Ezra 2:69, and Nehemiah 7:70 see Bochart IIieroz. P. II. Lib. iv. c. xxv. p. 617. This species of treasure is mentioned by Virgil;

Dives equom, dives pictai vestis et auri.

Aeneid ix. 26.

The reason why wealth consisted so much in changes of raiment, is to be found in the fondness for display in Oriental countries, and in the fact that as fashions never change there, such treasures are valuable until they are worn out. In the ever-varying fashions of the West such treasures are comparatively of much less value.

As the clay - As the dust of the streets; or as abundant as mire.

Job 27:16 Parallel Commentaries

The Sinner Arraigned and Convicted.
1. Conviction of guilt necessary.--2. A charge of rebellion against God advanced.--3. Where it is shown--that all men are born under God's law.--4. That no man hath perfectly kept it.--5. An appeal to the reader's conscience on this head, that he hath not.--6. That to have broken it, is an evil inexpressibly great.--7. Illustrated by a more particular view of the aggravations of this guilt, arising--from knowledge.--8. From divine favors received.--9. From convictions of conscience overborne.--10. …
Philip Doddridge—The Rise and Progress of Religion in the Soul