Romans 1:19-21

because that which is known about God is evident within them [in their inner consciousness], for God made it evident to them. For ever since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through His workmanship [all His creation, the wonderful things that He has made], so that they [who fail to believe and trust in Him] are without excuse and without defense. [Ps 19:1-4; Eph 2:10] For even though they knew God [as the Creator], they did not honor Him as God or give thanks [for His wondrous creation]. On the contrary, they became worthless in their thinking [godless, with pointless reasonings, and silly speculations], and their foolish heart was darkened.