Monism is the belief that there is one thing that makes up all others. Considering what I've seen of Kabbalah, it is thought by Jews that God makes up everything in the ten sephirah- All we know is apparently of Malkhut, and that is an emanation of God.
Even on a scientific level this holds true, because in the big bang there was a singularity, a unity. Of that came all things, but in the beginning there was really only one type of stuff (Likely super-heated plasma particles) that rearranged into every chemical we know. Even the chemicals we have now are made of the same stuff, varying only in charge and arrangement.
Does Monism seem to make sense to you in a religious sense? Are all things part of one thing, in different forms of purity and arrangement?