Deuternomy 4:24 For the LORD thy God is a consuming fire, even a jealous God.
God is a jealous God. That word means full of eagerness. It speaks of being fully and passionately engaged. The word means be apprehensive of rivalship. It wouild mean that God demands that we serve Himand Him only. God is jealous over His people like a husband or wife over the other. God will not allow you to love Him and another god. We must choose.
I think it is interesting that God would use this word about Himself. It has such a harsh meaning. I fully understand that I would expect no less than full devotion from my wife, and I believe you agree. Then why do we find the fact that God wants us dedicated only to Him to be so repugnant?
With God, it is all or nothing. You believe Him, or you do not. You love and serve Him, or you do not. No middle ground with God because all must choose.