Holy Bible: 1 JOHN 2:4

"He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him."

Whoever says that they believe in God: observe their ways. Do they obey God's commandments? Or do they just say that they believe, without evidence of faith?

Believing in God—knowing God—is believing in everything he says. He told us to obey his commandments, or we will suffer in hell, forever.