Romans 1:21

¹⁹ For what may be known about God is plain to them, because God has made it plain to them.

²⁰ For since the creation of the world God’s invisible qualities, His eternal power and divine nature, have been clearly seen, being understood from His workmanship, so that men are without excuse.

For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts.

²² Although they claimed to be wise, they became fools,

²³ and exchanged the glory of the immortal God for images of mortal man and birds and animals and reptiles.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB: For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts.
KJV: Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.
WEB: Because knowing God, they didn’t glorify him as God, and didn’t give thanks, but became vain in their reasoning, and their senseless heart was darkened.
ASV: 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.
DARBY: Because, knowing God, they glorified [him] not as God, neither were thankful; but fell into folly in their thoughts, and their heart without understanding was darkened:
BLB: For having known God, not as God did they glorify [Him], or give thanks, but they became futile in their thoughts and their foolish heart was darkened.

ÅB: for selv om de kjente Gud, gav de ham ikke takksigelsen og æren som tilfaller Gud, men de ble fordervet i tankene sine, og deres uforstandige hjerte ble formørket.
OTB: For selv om de kjente Gud, æret de ham verken som Gud eller takket ham, men deres tanker ble meningsløse og deres uforstandige hjerter ble formørket.
B1930: fordi de, enda de kjente Gud, dog ikke æret eller takket ham som Gud, men blev dårlige i sine tanker, og deres uforstandige hjerte blev formørket.

Study notes (Tyndale)

Original text and word study

Cross references

Ephesians 4:17–18
So I tell you this, and insist on it in the Lord, that you must no longer walk as the Gentiles do, in the futility of their thinking.
Read in context
2 Kings 17:15
They rejected His statutes and the covenant He had made with their fathers, as well as the decrees He had given them. They pursued worthless idols and themselves became worthless, going after the surrounding nations that the LORD had commanded them not to imitate.
Read in context
Jeremiah 2:5
This is what the LORD says: “What fault did your fathers find in Me that they strayed so far from Me, and followed worthless idols, and became worthless themselves?
Read in context
2 Timothy 3:2
For men will be lovers of themselves, lovers of money, boastful, arrogant, abusive, disobedient to their parents, ungrateful, unholy,
Read in context
Psalms 50:23
He who sacrifices a thank offering honors Me, and to him who rights his way, I will show the salvation of God.”
Read in context
John 3:19
And this is the verdict: The Light has come into the world, but men loved the darkness rather than the Light because their deeds were evil.
Read in context
Revelation 14:7
And he said in a loud voice, “Fear God and give Him glory, because the hour of His judgment has come. Worship the One who made the heavens and the earth and the sea and the springs of waters.”
Read in context
Psalms 81:12
So I gave them up to their stubborn hearts to follow their own devices.
Read in context