Their idols This contrast is introduced for the purpose of confirming the faith of the godly, by which they repose upon God alone; because, excepting him, all that the minds of men imagine of divinity is the invention of folly and delusion. To know the error and the madness of the world certainly contributes in no small degree to the confirmation of true godliness; while, on the other hand, a God is presented to us, whom we know assuredly to be the maker of heaven and earth, and whom we are to worship, not without reason or at random. The more effectually to silence the arrogance of the ungodly, who proudly presume to set at nought God and his chosen people, he contemptuously ridicules their false gods, first calling them idols, that is to say, things of nought, and, next, showing from their being formed of inanimate materials, that they are destitute of life and feeling. For can there be anything more absurd than to expect assistance from them, since neither the materials of which they are formed, nor the form which is given to them by the hand of men, possess the smallest portion of divinity so as to command respect for them? At the same time, the prophet tacitly indicates that the value of the material does not invest the idols with more excellence so that they deserve to be more highly esteemed. Hence the passage may be translated adversatively, thus, Though they are of gold and silver, yet they are not gods, because they are the work of men's hands. Had it been his intention merely to depreciate the substance of which they were composed, he would rather have called them wood and stone, but at present he speaks only of gold and silver. In the meantime, the prophet reminds us that nothing is more unbecoming than for men to say that they can impart either essence, or form, or honor to a god, since they themselves are dependent upon another for that life which will soon disappear. From this it follows, that the heathen vainly boast of receiving help from gods of their own devising. Whence does idolatry take its origin but from the imaginations of men? Having abundance of materials supplied to their hand, they can make of their gold or silver, not only a goblet or some other kind of vessel, but also vessels for meaner purposes, but they prefer making a god. And what can be more absurd than to convert a lifeless mass into some new deity? Besides, the prophet satirically adds, that while the heathen fashion members for their idols, they cannot enable them to move or use them. It is on this account that the faithful experience their privilege to be the more valuable, in that the only true God is on their side, and because they are well assured that all the heathen vainly boast of the aid which they expect from their idols, which are nothing but shadows. This is a doctrine, however, which ought to receive a greater latitude of meaning; for from it we learn, generally, that it is foolish to seek God under outward images, which have no resemblance or relation to his celestial glory. To this principle we must still adhere, otherwise it would be easy for the heathen to complain that they were unjustly condemned, because, though they make for themselves idols upon earth, they yet were persuaded that God is in heaven. They did not imagine that Jupiter was either composed of stone, or of gold, or of earth, but that he was merely represented under these similitudes. Whence originated this form of address common among the ancient Romans, "To make supplication before the gods," but because they believed the images to be, as it were, the representations of the gods? The Sicilians, says Cicero, have no gods before whom they can present their supplications. He would not have spoken in this barbarous style, had the notion not been prevalent, that the figures of the heavenly deities were represented to them in brass, or silver, or in marble; [1] and cherishing the notion, that in approaching these images the gods were nearer to them, the prophet justly exposes this ridiculous fancy, that they would enclose the Deity within corruptible representations, since nothing is more foreign to the nature of God than to dwell under stone, or a piece of marble, or wood, and stock of a tree, or brass, or silver. [2] For this reason, the prophet Habakkuk designates that gross mode of worshipping God, the school of falsehood. (Habakkuk 2:18.) Moreover, the scornful manner in which he speaks of their gods deserves to be noticed, they have a mouth, but they do not speak; for why do we betake ourselves to God, but from the conviction that we are dependent upon him for life; that our safety is in him, and that the abundance of good, and the power to help us, are with him? As these images are senseless and motionless, what can be more absurd than to ask from them that of which they themselves are destitute?

Footnotes

1 - But though these images might, at first, be intended merely to bring the real Deity before the senses, and thus to impress the mind the more deeply with sentiments of awe and devotion, yet in process of time they began to be considered, especially by the ignorant multitude, as being really gods.

2 - The heathen not only considered their idols or images as representing their gods, but believed that, when consecrated by their priests, they were thereby animated by the gods whom they represented, and hence were worshipped as such. "Augustine (De Civitate Dei, B. 8, c. 23) tells us of the theology of the heathen, received from Trismegistus, that statues were the bodies of their gods, which, by some magical ceremonies, or theourgiai, were forced to join themselves as souls, and so animate and enliven those dead organs, to assume and inhabit them. And so Proclus (De Sacrif et Mag.) mentions it as the common opinion of the Gentiles, that the gods were, by their favor and help, present in their images;' and, therefore, the Tyrians, fearing that Apollo would forsake them, bound his image with golden chains, supposing then the god could not depart from them. The like did the Athenians imagine when they clipped the wings of the image of Victory; and the Sicilians, in Cicero, (De Divin.) who complain that they had no gods in their island, because Verres, Praetor in Sicily, had taken away all their statues. And so we know Laban, when he had lost his Teraphim, tells Jacob, (Genesis 31:30,) that he had stolen his gods;' and so of the golden calf, after the feasts of consecration, proclamation is made before it, These be thy gods, O Israel!' But this of the animation and inspiriting of images, by their rites of consecration, being but a deception and fiction of their priests, the Psalmist here discovers it, and assures all men that they are as inanimate and senseless after the consecration as before; base silver and gold, with images of mouths and ears, etc., but without any power to use any of them, and, consequently, most unable to hear or help their votaries." -- Hammond

Their idols - Their gods - the gods which they worship, as contrasted with the God whom we adore. The design of this description Psalm 115:4-8 is to show the utter vanity of trusting in such gods, and to lead the people of Israel to put their trust in the true God - in Yahweh.
Are silver and gold - Made of silver and gold, and they must have, therefore, the properties of silver and gold. They can be of value only as silver and gold. They cannot do the work of mind; they cannot do the work of God. The psalmist was not disposed to depreciate the real value of these idols, or to throw contempt on them which they did not deserve. He was disposed to treat them fairly. They were silver and gold; they had an intrinsic value as such; they showed in the value of the material how much the pagan were disposed to honor their objects of worship; and they were not held up to contempt as shapeless blocks of wood or stone. The psalmist might have said that most of them were made of wood or stone, and were mere shapeless blocks; but it is always best to do justice to an adversary, and not to attempt to underrate what he values. The argument of an infidel on the subject of religion may be utterly worthless as an argument for infidelity, but it may evince ability, learning, subtilty, clearness of reasoning, and even candor; and it is best to admit this, if it is so, and to give to it all the credit which it deserves as a specimen of reasoning, or as stating a real difficulty which ought to be solved by somebody - to call it "silver and gold" if it is so, and not to characterize it as worthless, weak, stupid - the result of ignorance and folly. He has great advantage in an argument who owns the real force of what an opponent says; he gains nothing who charges it as the offspring of stupidity, ignorance, and folly - unless he can show that it is so.
The work of men's hands - Shaped and fashioned by people's hands. They cannot, therefore, be superior to those who made them; they cannot answer the purpose of a God.

Their idols are silver, etc. - They are metal, stone, and wood. They are generally made in the form of man, but can neither see, hear, smell, feel, walk, nor speak. How brutish to trust in such! And next to these, in stupidity and inanity, must they be who form them, with the expectation of deriving any good from them. So obviously vain was the whole system of idolatry, that the more serious heathens ridiculed it, and it was a butt for the jests of their freethinkers and buffoons. How keen are those words of Juvenal! -
- Audis Jupiter, haec? nec labra moves, cum mittere vocem.
Debueras, vel marmoreus vel aheneus? aut cur
In carbone tuo charta pia thura soluta
Ponimus, et sectum vituli jecur, albaque porci
Omenta? ut video, nullum discrimen habendum est.
Effigies inter vestras, statuamque Bathylli.
Sat. xiii., ver. 113.
Dost thou hear, O Jupiter, these things? nor move thy lips when thou oughtest to speak out, whether thou art of marble or of bronze? Or, why do we put the sacred incense on thy altar from the opened paper, and the extracted liver of a calf, and the white caul of a hog? As far as I can discern there is no difference between thy statue and that of Bathyllus."
This irony will appear the keener, when it is known that Bathyllus was a fiddler and player, whose image by the order of Polycrates, was erected in the temple of Juno at Samos. See Isaiah 41:1, etc.; Isaiah 46:7; Jeremiah 10:4, Jeremiah 10:5, etc.; and Psalm 135:15, Psalm 135:16.

Their idols [are] (d) silver and gold, the work of men's hands.
(d) Seeing that neither the matter nor the form can commend their idols it follows that there is no reason that they should be esteemed.

Their idols are silver and gold,.... The idols of the Gentiles; so the Septuagint, Vulgate Latin, Syriac, Arabic, and Ethiopic versions. The gods they serve and worship are not in the heavens; but the matter of which they are made is dug out of the earth: and this is the greatest excellency and value that there is in them; and such as are made of these are of the greatest worth, and yet only for the matter of them, otherwise useless and inanimate statues; such are the idols of the Papists, Revelation 9:20.
The work of men's hands; the matter of them is gold and silver, which they owe to the earth as their original; the form of them they owe to men, and therefore can not be God, Hosea 8:6. If it is idolatry to worship what God has made, the sun, moon, and stars, it must be gross idolatry, and great stupidity, to worship what man has made: if it is sinful to worship the creature besides the Creator, or more than him, it must be still more so to worship the creature of a creature.

(Compare Isaiah 40:18-20; Isaiah 44:9-20).