And changed, etc. Having feigned such a God as they could comprehend according to their carnal reason, they were very far from acknowledging the true God: but devised a fictitious and a new god, or rather a phantom. And what he says is, that they changed the glory of God; for as though one substituted a strange child, so they departed from the true God. Nor are they to be excused for this pretense, that they believe that God dwells in heaven, and that they count not the wood to be God, but his image; for it is a high indignity to God, to form so gross an idea of his majesty as to dare to make an image of him. But from the wickedness of such a presumption none were exempt, neither priests, nor statesmen, nor philosophers, of whom the most sound-minded, even Plato himself, sought to find out some likeness of God. The madness then here noticed, is, that all attempted to make for themselves an image of God; which was a certain proof that their notions of God were gross and absurd. And, first, they befouled the majesty of God by forming him in the likeness of a corruptible man: for I prefer this rendering to that of mortal man, which is adopted by Erasmus; for Paul sets not the immortality of God in opposition to the mortality of man, but that glory, which is subject to no defects, to the most wretched condition of man. And then, being not satisfied with so great a crime, they descended even to beasts and to those of the most filthy kind; by which their stupidity appeared still more evident. You may see an account of these abominations in Lactantius, in Eusebius, and in Augustine in his book on the city of God.

And changed - This does not mean that they literally "transmuted" God himself; but that in their views they exchanged him; or they changed him "as an object of worship" for idols. They produced, of course, no real change in the glory of the infinite God, but the change was in themselves. They forsook him of whom they had knowledge Romans 1:21, and offered the homage which was due to him, to idols.
The glory - The majesty, the honor, etc. This word stands opposed here to the "degrading" nature of their worship. Instead of adoring a Being clothed with majesty and honor, they bowed down to reptiles, etc. They exchanged a glorious object of worship for what was degrading and humiliating. The glory of God, in such places as this, means his essential honor, his majesty, the concentration and expression of his perfections, as the glory of the sun, 1-Corinthians 15:41 means his shining, or his splendor; compare Jeremiah 2:11; Psalm 106:20.
The uncorruptible God - The word "uncorruptible" is here applied to God in opposition to "man." God is unchanging, indestructible, immortal. The word conveys also the idea that God is eternal. As he is incorruptible, he is the proper object of worship. In all the changes of life, man may come to him, assured that he is the same. When man decays by age or infirmities, he may come to God, assured that he undergoes no such change, but is the same yesterday, today, and forever; compare 1-Timothy 1:17.
Into an image - An image is a representation or likeness of anything, whether made by painting, or from wood, stone, etc. Thus, the word is applied to "idols," as being "images" or "representations" of heavenly objects; 2-Chronicles 33:7; Daniel 3:1; Revelation 11:4, etc. See instances of this among the Jews described in Isaiah 40:18-26, and Ezekiel 8:10.
To corruptible man - This stands opposed to the "incorruptible" God. Many of the images or idols of the ancients were in the forms of men and women. Many of their gods were heroes and benefactors, who were deified, and to whom temples, altars, and statues were erected. Such were Jupiter, and Hercules, and Romulus, etc. The worship of these heroes thus constituted no small part of their idolatry, and their images would be of course representations of them in human form. It was proof of great degradation, that they thus adored human beings with like passions as themselves; and attempted to displace the true God from the throne, and to substitute in his place an idol in the likeness of men.
And to birds - The "ibis" was adored with special reverence among the Egyptians, on account of the great benefits resulting from its destroying the serpents which, but for this, would have overrun the country. The hawk was also adored in Egypt, and the eagle at Rome. As one great principle of pagan idolatry was to adore all objects from which important benefits were derived, it is probable that all birds would come in for a share of pagan worship, that rendered service in the destruction of noxious animals.
And fourfooted beasts - Thus, the ox, under the name "apis," was adored in Egypt; and even the dog and the monkey. In imitation of the Egyptian ox, the children of Israel made their golden calf, Exodus 22:4. At this day, two of the most sacred objects of worship in Hindostan are the cow and the "monkey."
And creeping things - Reptiles. "Animals that have no feet, or such short ones that they seem to creep or crawl on the ground." "(Calmet.)" Lizards, serpents, etc. come under this description. The "crocodile" in Egypt was an object of adoration, and even the serpent so late as the second century of the Christian era, there was a sect in Egypt, called "Ophites" from their worshipping a serpent, and who ever claimed to be Christians, (Murdock's Mosheim, vol. i. p. 180, 181). There was scarcely an object, animal or vegetable, which the Egyptians did not adore. Thus, the leek, the onion, etc. were objects of worship, and people bowed down and paid adoration to the sun and moon, to animals, to vegetables, and to reptiles. Egypt was the source of the views of religion that pervaded other nations, and hence, their worship partook of the same wretched and degrading character. (See "Leland's" "Advantage and Necessity of Revelation.")

They changed the glory, etc. - The finest representation of their deities was in the human figure; and on such representative figures the sculptors spent all their skill; hence the Hercules of Farnese, the Venus of Medicis, and the Apollo of Belvidere. And when they had formed their gods according to the human shape, they endowed them with human passions; and as they clothed them with attributes of extraordinary strength, beauty, wisdom, etc., not having the true principles of morality, they represented them as slaves to the most disorderly and disgraceful passions; excelling in irregularities the most profligate of men, as possessing unlimited powers of sensual gratification.
And to birds - As the eagle of Jupiter among the Romans, and the ibis and hawk among the Egyptians; which were all sacred animals.
Four-footed beasts - As the apis or white ox among the Egyptians; from which the idolatrous Israelites took their golden calf. The goat, the monkey, and the dog, were also sacred animals among the same people.
Creeping things - Such as the crocodile and scarabeus, or beetle, among the Egyptians.

And changed the glory of the (h) uncorruptible God into an image made like to corruptible man, and to birds, and fourfooted beasts, and creeping things.
(h) For the true God they substituted another.

And changed the glory of the incorruptible God,.... God is incorruptible and immortal in his nature, and so is opposed to all corruptible creatures and things: he has a glory which is essential to him, and a manifestative one in the creatures, and which is relative, and of right belongs to him: his absolute essential glory cannot be changed, cannot be taken away from him, nor given to another; but his relative glory may be said to be changed, when another is worshipped in his stead, and called by his name. So Philo the Jew (g) speaks of
"some, who, leaving the true God, make to themselves false ones, and impose the name of the eternal and incorruptible upon created and corruptible beings.''
Into an image made like to corruptible man; which was worshipped in different forms by the several nations of the world:
and to birds; as the dove by the Samaritans, the hawk, the ibis, and others by the Egyptians:
and fourfooted beasts; as the ox, and other creatures:
and creeping things; such as beetles, serpents, and others, by the same.
(g) De Vita Mosis, l. 3. p. 678, 679.

And changed--or "exchanged."
the glory of the uncorruptible God into--or "for"
an image . . . like to corruptible man--The allusion here is doubtless to the Greek worship, and the apostle may have had in his mind those exquisite chisellings of the human form which lay so profusely beneath and around him as he stood on Mars' Hill; and "beheld their devotions." (See on Acts 17:29). But as if that had not been a deep enough degradation of the living God, there was found "a lower deep" still.
and to birds, and four-footed beasts, and to creeping things--referring now to the Egyptian and Oriental worship. In the face of these plain declarations of the descent of man's religious belief from loftier to ever lower and more debasing conceptions of the Supreme Being, there are expositors of this very Epistle (as REICHE and JOWETT), who, believing neither in any fall from primeval innocence, nor in the noble traces of that innocence which lingered even after the fall and were only by degrees obliterated by wilful violence to the dictates of conscience, maintain that man's religious history has been all along a struggle to rise, from the lowest forms of nature worship, suited to the childhood of our race, into that which is more rational and spiritual.

And changed - With the utmost folly. Here are three degrees of ungodliness and of punishment: the first is described, Romans 1:21-24; the second, Romans 1:25-27; the third, in Romans 1:28, and following verses. The punishment in each case is expressed by God gave them up. If a man will not worship God as God, he is so left to himself that he throws away his very manhood. Reptiles - Or creeping things; as beetles, and various kinds of serpents.