Romans 1:21-23

because, although they know who God is, they do not glorify him as God or thank him. On the contrary, they have become futile in their thinking; and their undiscerning hearts have become darkened.

Claiming to be wise, they have become fools!

In fact, they have exchanged the glory of the immortal God for mere images, like a mortal human being, or like birds, animals or reptiles!