On the "proofreading" front, note that you'd need something like ...so we can understand the cause, making it easier to... (OP's text as presented is simply ungrammatical at the highlighted points).
Regarding the choice between to rule ourselves and to rule our self, there's a certain amount of "wiggle room". But the situation is complicated by the fact that there are two significantly different semantic nuances that don't correspond to the simplistic "grammatical / logical" distinctions.
Ordinarily, We must rule ourselves (single-word reflexive form) will be understood as meaning that we (not someone else) must be in charge of our affairs. But consider...
We must not let our head rule our heart.
There will always be pedants who insist that should be heads and hearts (which is admittedly more common), but as I have pointed out on ELU, I'm not one of them. So from my point of view...
In order to truly exercise self-control, we must learn to rule our self
...is a perfectly valid construction. And it has the advantage of putting plenty of syntactic distance between the two different possible meanings:
1: to rule oneself rather than being ruled by others
2: to rule one's self = id = ego as opposed to controlling, say, one's appetite, or children.
TL;DR: It depends what meaning you intend, but if you want #2 above there are strong arguments for using the singular form in this exact context, because even if you explicitly write it as two words, the reader is likely to be misled into assuming sense #1.
Note that this isn't so much of a problem in speech, where you stress self/selves for sense #2.