Who changed, etc. He repeats what he had said before, though in different words, in order to fix it deeper in our minds. When the truth of God is turned to a lie, his glory is obliterated. It is then but just, that they should be besprinkled with every kind of infamy, who strive to take away from God his honor, and also to reproach his name. -- And worshipped, etc. That I might include two words in one, I have given this rendering. He points out especially the sin of idolatry; for religious honor cannot be given to a creature, without taking it away, in a disgraceful and sacrilegious manner, from God: and vain is the excuse that images are worshipped on God's account, since God acknowledges no such worship, nor regards it as acceptable; and the true God is not then worshipped at all, but a fictitious God, whom the flesh has devised for itself. [1] What is added, Who is blessed for ever, I explain as having been said for the purpose of exposing idolaters to greater reproach, and in this way, "He is one whom they ought alone to have honored and worshipped, and from whom it was not right to take away any thing, no, not even the least."

Footnotes

1 - The words, "the truth of God," and "falsehood," or, a lie, are Hebraistic in their meaning, signifying "the true God," and "an idol." The word, which means a lie, is often in Hebrew applied to any thing made to be worshipped. See Isaiah 44:17, compared with 20; Jeremiah 13:25 Stuart renders the sentence, "Who exchanged the true God for a false one." Wolfius objects to this view, and says, "I prefer to take aletheian tou theou, for the truth made known by God to the Gentiles, of which see Romans 1:18, and the following verses: they changed this into a lie, i.e., into those insane and absurd notions, into which they were led by their dialogismois -- reasonings, Romans 1:21." The expression -- para ton ktisanta has been rendered by Erasmus, "above the creator," by Luther, "rather than the Creator;" by Beza, "to the neglect of the Creator -- præterito conditore;" and by Grotius, "in the place of the Creator." The two last are more consonant with the general tenor of the context; for the persons here spoken of, according to the description given them, did not worship God at all; para is evidently used in the sense of exclusion and opposition para ton nomon -- contrary to the law, Acts 18:13; para phusin -- contrary to nature, Romans 1: 26. See Galatians 1:8 -- Ed.

Who changed the truth of God - This is a repetition of the declaration in Romans 1:23, in another form. The phrase, "the truth of God" is a Hebrew phrase, meaning "the true God." In such a case, where two nouns come together, one is employed as an adjective to qualify the other. Most commonly the latter of two nouns is used as the adjective, but sometimes it is the former, as in this case. God is called "the true God" in opposition to idols, which are called false gods. There is but one real or true God, and all others are false.
Into a lie - Into idols, or false gods. Idols are not infrequently called falsehood and lies, because they are not true representations of God; Jeremiah 13:25; Isaiah 28:15; Jeremiah 10:14; Psalm 40:4.
The creature - Created things, as the sun, moon, animals, etc.
Who is blessed forever - It was not uncommon to add a doxology, or ascription of praise to God, when his name was mentioned; see Romans 9:5; 2-Corinthians 11:31; Galatians 1:5. The Jews also usually did it. In this way they preserved veneration for the name of God, and accustomed themselves to speak of him with reverence. "The Muslims also borrowed this custom from the Jews, and practice it to a great extent. Tholuck mentions an Arabic manuscript in the library at Berlin which contains an account of heresies in respect to Islamism, and as often as the writer has occasion to mention the name of a new heretical sect, he adds, 'God be exalted above all which they say'" (Stuart).
Amen - This is a Hebrew word denoting strong affirmation. So let it be. It implies here the solemn assent of the writer to what was just said; or his strong wish that what he had said might be - that the name of God might be esteemed and be blessed forever. The mention of the degrading idolatry of the pagans was strongly calculated to impress on his mind the superior excellency and glory of the one living God. It is mentioned respecting the honorable Robert Boyle, that he never mentioned the name of God without a solemn pause, denoting his profound reverence. Such a practice would tend eminently to prevent an unholy familiarity and irreverence in regard to the sacred name of the Most High; compare Exodus 20:7.

Changed the truth of God into a lie - In the place of the true worship of God, they established idolatry. In various places of Scripture idols are termed lies. Isaiah 44:20; Jeremiah 10:14; Jeremiah 13:25. The true God was known among the primitive inhabitants of the earth, those who first became idolaters literally changed the truth of God into a lie: they did know the true God, but they put idols in his place.

Who changed the truth of God into a lie,.... Not the truth of the Gospel, which they were unacquainted with; but that which might be known of God as true, and was known of them by the light of nature; or the true God himself, whom they "changed into a lie"; by ascribing to false deities, which were lying vanities, those things which were known of God; and by worshipping them instead of him: for they
worshipped and served the creature more than the Creator; or "above him" or "against him", in opposition to him, or "besides him", others along with him; or neglecting him, and not worshipping him at all; which is aggravated in that what they worshipped was a creature, either of their own, or of God's making, and whom they neglected was the Creator of them:
who is blessed for ever, Amen; is blessed in himself, and the fountain of all blessedness to his creatures; which is so glaring a truth, that everyone ought to say and set his "Amen" to it.

Who changed the truth of God into a lie--that is, the truth concerning God into idol falsehood.
and worshipped and served the creature more than the Creator--Professing merely to worship the Creator by means of the creature, they soon came to lose sight of the Creator in the creature. How aggravated is the guilt of the Church of Rome, which, under the same flimsy pretext, does shamelessly what the heathen are here condemned for doing, and with light which the heathen never had!
who is blessed for ever! Amen--By this doxology the apostle instinctively relieves the horror which the penning of such things excited within his breast; an example to such as are called to expose like dishonor done to the blessed God.

Who changed the truth - The true worship of God. Into a lie - False, abominable idolatries. And worshipped - Inwardly. And served - Outwardly.