Romans 1:21

When they knew God. Or, “although they knew God,” that is, through the revelation of conscience and nature (see on v. 20). Furthermore, God-fearing men like Noah and his sons knew God, and this knowledge they passed on their children. But because of sinful neglect, the minds of most of their descendants soon became darkened, and the knowledge of God was largely lost among the Gentiles.

Glorified him not. The unwillingness to honor God as the divine Creator was the real source of the darkened minds and abominable practices of the Gentiles. To glorify God means to reverence, love, and obey Him.

Neither were thankful. Unwillingness to give thanks to God for His love and goodness toward men is one of the causes of corruption and idolatry. Ingratitude hardens the heart and leads men to forget the Being to whom they are unwilling to express thankfulness.

Became vain. Gr. mataioo, “to become foolish,” or “to become futile.” In devising vanities, the Gentiles themselves had become vain and foolish. The human mind that worships dumb idols of wood and stone becomes like the objects of its worship (Ps. 115:8). Compare kenos, also translated “vain” (see on 1 Cor. 15:10), but meaning “empty,” or “hollow.”

Imaginations. Gr. dialogismoi, “reasonings,” “thoughts,” “speculations.” Paul is using the term to refer to the futile ideas and speculations that the Gentiles had come to hold regarding God in opposition to the truth that they had once known and that was still set before them in God’s created works (v. 20).

Foolish. Gr. asunetos, literally, “without understanding” (see Matt. 15:16), hence, “unintelligent,” “senseless.”

Heart. A comprehensive term used for all the human faculties of thought (Rom. 10:6), will (1 Cor. 4:5), or feeling (Rom. 9:2). The Jews regarded the heart as the seat of man’s inner life. It may be the home of the Holy Spirit (Eph. 5:5), or of evil desires (Rom. 1:24; cf. Mark 7:21-23).

Was darkened. Men had sunk so deep in ignorance and sin that their minds had become dark and senseless, and they no longer perceived or understood the truth. To produce such darkness has ever been Satan’s purpose in the great controversy. God has given to every man “individuality, power to think and to do” (Ed 17). Salvation depends upon the right exercise and development of this power in choosing to have faith in God and to obey His will. Consequently, for six thousand years it has been Satan’s studied purpose to weaken and destroy this God-given power, that men may become helplessly incapable of recognizing, receiving, and practicing the truth.

Therefore, one of the first and most necessary promises of the gospel is that God will give to man a new heart or mind (Eze. 36:26; cf. John 3:3). “The words, ‘A new heart also will I give you’ . . ., mean, A new mind will I give you” (CT 452). That this marvelous transformation of heart and mind has been made possible for everyone who has faith in Christ is Paul’s message in the Epistle to the Romans.