Look up to the skies. Who created all these stars? He leads out the army of heaven one by one and calls all the stars by name. Because he is strong and powerful, not one of them is missing.
There are things about him that people cannot see—his eternal power and all the things that make him God. But since the beginning of the world those things have been easy to understand by what God has made. So people have no excuse for the bad things they do.
(Those who are not Jews do not have the law, but when they freely do what the law commands, they are the law for themselves. This is true even though they do not have the law.