Albert Barnes Commentary Romans 1:21

"because that, knowing God, they glorified him not as God, neither gave thanks; but became vain in their reasonings, and their senseless heart was darkened." — Romans 1:21 (ASV)

Because that. The apostle here is showing that it was right to condemn people for their sins. To do this it was necessary to show them that they had the knowledge of God, and the means of knowing what was right; and that the true source of their sins and idolatries was a corrupt and evil heart.

When they knew God. In Greek, knowing God. That is, they had an acquaintance with the existence and many of the perfections of one God. There can be no doubt that many of the philosophers of Greece and Rome had a knowledge of one God. This was undoubtedly the case with Pythagoras, who had traveled extensively in Egypt, and even in Palestine, and also with Plato and his disciples.

This point is clearly shown by Cudworth in his Intellectual System, and by Bishop Warburton in the Divine Legation of Moses. Yet the knowledge of this great truth was not communicated to the people. It was confined to the philosophers; and not improbably, one design of the mysteries celebrated throughout Greece was to keep up the knowledge of the one true God.

Gibbon has remarked that "the philosophers regarded all the popular superstitions as equally false; the common people as equally true; and the politicians as equally useful." This was probably a correct account of the prevalent feelings among the ancients. A single extract from Cicero (De Natura Deorum, Book 2, Chapter 6) will show that they had the knowledge of one God: "There is something in the nature of things Which the mind of man, which reason, which human power cannot effect; and certainly that which produces this must be better than man. What can this be called but God?" Again (Book 2, Chapter 2), "What can be so plain and manifest, when we look at heaven, and contemplate heavenly things, as that there is some Divinity of most excellent mind, by which these things are governed?"

They glorified him not as God. They did not honour him as God. This was the true source of their abominations. To glorify him as God is to regard with proper reverence all his perfections and laws; to venerate his name, his power, his holiness, and presence, and so on. As they were not inclined to do this, so they were given over to their own vain and wicked desires. Sinners are not willing to give honour to God as God. They are not pleased with his perfections; and therefore the mind becomes fixed on other objects, and the heart gives free indulgence to its own sinful desires. A willingness to honour God as God—to reverence, love, and obey him—would effectually restrain people from sin.

Neither were thankful. The obligation to be thankful to God for his mercies, for the goodness which we experience, is plain and obvious. Thus we judge of favors received from our fellow human beings. The apostle here clearly regards this unwillingness to render gratitude to God for his mercies as one of the causes of their subsequent corruption and idolatry. The reasons for this are the following:

1. The effect of ingratitude is to render the heart hard and insensible.

2. People seek to forget the Being to whom they are unwilling to exercise gratitude.

3. To do this, they fix their affections on other things; and hence the heathen expressed their gratitude not to God, but to the sun, and moon, and stars, and so on—the media by which God bestows his favors on humankind.

And we may learn here that an unwillingness to thank God for his mercies is one of the most certain causes of alienation and hardness of heart.

But became vain. To become vain, in our common understanding, means to be elated, self-conceited, or to seek praise from others. The meaning here seems to be that they became foolish and frivolous in their thoughts and reasonings. They acted foolishly; they employed themselves in useless and frivolous questions, the effect of which was to lead the mind further and further from the truth respecting God.

Imaginations. This word properly means thoughts, then reasonings, and also disputations. Perhaps our word speculations would convey its meaning here. It implies that because they were unwilling to honor him, they commenced those speculations which resulted in all their vain and foolish opinions about idols, and the various rites of idolatrous worship. Many of the speculations and inquiries of the ancients were among the most vain and senseless that the mind can conceive.

And their foolish heart. The word heart is not infrequently used to denote the mind or the understanding. We apply it to denote the affections. But such was not its common use among the Hebrews. We speak of the head when we refer to the understanding, but this was not the case with the Hebrews. They spoke of the heart in this manner, and in this sense it is clearly used in this place. (Romans 2:15; 2 Corinthians 4:6; 2 Peter 1:19).

The word foolish literally means that which is without understanding (Matthew 15:16).

Was darkened. It was rendered obscure, so that they did not perceive and comprehend the truth. The process stated in this verse is as follows:

1. That people had the knowledge of God;

2. That they refused to honour him when they knew him, and were opposed to his character and government;

3. That they were ungrateful;

4. That they then began to doubt, to reason, to speculate, and wandered far into darkness. This is substantially the process by which people wander away from God now. They have the knowledge of God, but they do not love him; and being dissatisfied with his character and government, they begin to speculate, fall into error, and then "find no end in wandering mazes lost," and sink into the depths of heresy and of sin.