In Christianity, Satan is God’s contender. In Judaism, why doesn’t God have a contender? Is there a contradiction?

Well, yes, there is a contradiction between Christianity and Judaism but no contradiction inside either religion.

İn Judaism, God is the God of all, the single unity on which everything else is dependent for its existence. İn Jewish mysticism, God is literally the only thing that exists and everything else is just part of the divine reflection, distorted to create the illusion of independent existence.

So, of course God can have no contenders. İt’s like believing the antagonist from a video game can do ne real harm- it’s just impossible.

Among many Christians however, they seem to believe God is a distinct being that is separate from creation and prone to rebellion by his angels. Separate beings exist and have their own, independent existence while God floats around judging them.

İn such a system, there is room for a rebellious Satan.

Of course, the Jewish and Christian world views are fundamentally at odds but each is internal ly consistent.