Rashi explains that “This is the law of the Olah-offering,” is an inclusionary phrase. The Torah teaches us that one “law” includes all offerings that have been alu, placed on the Mizbayach, Altar. Even if they had been pesullin, disqualified, and therefore should not have been placed on the Mizbayach in the first place, we say: Im alu lo yeirdu, “If they ascend, they should not descend.” This is derived from Zos HaTorah – “Every instance that the Torah writes, ‘This is the law,’ it comes to include something.” In this case, all disqualified korbanos, which must be allowed to remain on the Mizbayach until they burn up, are included.
Horav Moshe, zl, m’Kubrin, renders this pasuk homiletically: Zos HaTorah – “This is the benefit/advantage of studying Torah.” Even those who, for some reason, later deviated and became pasul, disqualified, lo yeirdu, they will not descend. Any person who has studied Torah has been infused with a spiritual antibody that protects him forever. He is never lost. There is a GPS homing device imbedded deeply within him. He picked up this device when he studied Torah. It allows him to always find his way back home – to Torah, to observance, to Hashem. One who has once learned is never lost. The light of the Torah serves as a beacon to guide him back.