When one thinks privileges stop there, on more quick progress in the initial ranks, they're actually wrong.
Acquiring a powerful relic... just this simple act alone can help one jump directly to this rank.
Relics are generally tied to specific Laws, after all!
And where are they typically stored? Inside the Soul Zone itself.
So the Law Power problem that he is currently facing? With a suitable relic, it can be solved... even if not completely.
Anyway, here at the third rank, Law Bearer, one needs to significantly deepen his understanding in the law until finally he achieves 50% complete understanding in the said law, and when he does?
Then once again, congratulations, you have reached the fourth rank, Law Adept.
If someone at the first rank or the second rank in terms of strength are merely around the same level as ordinary people, just with slightly better perception.