Nefesh HaChayim, Reb Itzele's Long Annotation

Refer to the Zohar 31b that the light was hidden away for the righteous. And it closes there: “And it is hidden away for the righteous”—specifically for the righteous. The definition of “righteous” in all places is “righteous in behavior”, because it’s specifically via the actual physical performance of the commandments that the supernal lights that are hidden in Torah are aroused. And there are found the tzellem’s supernal roots. For that reason they (OBM) stated (Avot 3:12): “Anyone whose actions are greater in quantity than their wisdom, their wisdom is thereby preserved…”. For the primary thing [*] is that first he must be victorious over his inclination, to subjugate it to the performance of the commandments, even if he does not yet have the brains of the lamed of the tzellem.