Boiled down to it's essentials, your argument seems to be something like:
1. Finite minds cannot fully comprehend infinite things.
2. Human minds are finite.
3. God is infinite.
4. Therefore the human mind cannot fully comprehend God.
Logical arguments must have at least two premises, and in it's simplest form (syllogisms), that's ALL they have.
But, in practice, a valid logical argument (i.e. one in which the conclusion necessarily
follows from the premises), generally has any number of premises. Often the "next" premise is the conclusion from the initial logical proposition, and so on.
I believe the argument I just presented is logically valid.
For an essay, you don't usually state your premises in a single sentence. You generally explain them and give reasons why they are acceptable.
That appears to be what you are doing. That's fine. It doesn't make anything you say "illogical" just because it's not in the form of a syllogism.