Rashi on Leviticus 22:9/רש"י על ויקרא כ״ב:ט׳

1ושמרו את משמרתי THEY SHALL THEREFORE KEEP MY CHARGE — not to eat the heave-offering (as mentioned in v. 7) whilst they are in a state of bodily uncleanness (Sanhedrin 83a).

2ומתו בו LEST THEY DIE THEREBY — This phrase teaches us that this means death through Heaven (not through the sentence of the court) (cf. Sanhedrin 83a).