2 Kings 17 tells us about people that the King of Assyria populated Samaria with. They knew nothing of Yahweh, so worshiped their own gods. God sent lions among them and they petitioned the King to send a priest of Israel to teach them how to serve the god of the land. These henotheists (look that one up for yourself!), however, found that his was no better because God was infuriated that they served Him and other gods as well (vv. 32, 33, 41). They were as confused by such a mixture as are many today who try to serve the true God and, at the same time, some other god (usually of their own making) as well. God is displeased by such mixture, and though He will not send lions (not enough around), He will deal with this mixture. Whom do you serve? Yahweh? Some god of your own making?
Think carefully—mixture displeases the true God of the Bible. Do you really want to do so?