Jamieson, Fausset and Brown on Numbers 15:22

22. if ye have erred, and not observed all these commandments, &c.--respecting the performance of divine worship, and the rites and ceremonies that constitute the holy service. The law relates only to any omission and consequently is quite different from that laid down in Le 4:13, which implies a transgression or positive neglect of some observances required. This law relates to private parties or individual tribes; that to the whole congregation of Israel.