II Kings 17:15 And they rejected his statutes, and his covenant that he made with their fathers, and his testimonies which he testified against them; and they followed vanity, and became vain, and went after the heathen that were round about them, concerning whom the LORD had charged them, that they should not do like them.
Instead of following the God of heaven they followed the gods of the heathen. Those gods are vanity, emptiness. We are warned. There is only one true God. He is the creator and judge of the universe. Everyone wants you to be tolerant. They want you to accept that there are other gods but that is not true.
When you accept these others gods you are rejecting the true God. When you accept them you are following vanity. Your life will become vain, empty, worthless. Follow God!