Paul’s letter to the Romans, chapter 1, verses 18 through 24:
18 But God shows his anger from heaven against all sinful, wicked people who suppress the truth by their wickedness. 19 They know the truth about God because he has made it obvious to them. 20 For ever since the world was created, people have seen the earth and sky. Through everything God made, they can clearly see his invisible qualities—his eternal power and divine nature. So they have no excuse for not knowing God.
21 Yes, they knew God, but they wouldn’t worship him as God or even give him thanks. And they began to think up foolish ideas of what God was like. As a result, their minds became dark and confused. 22 Claiming to be wise, they instead became utter fools. 23 And instead of worshiping the glorious, ever-living God, they worshiped idols made to look like mere people and birds and animals and reptiles.
24 So God abandoned them to do whatever shameful things their hearts desired. As a result, they did vile and degrading things with each other’s bodies.
Yep...that’s it. I always cringe just a bit when I read those words.