God being pleased to spare them, either because they disowned their father's act, and thereupon separated themselves both from his tent and company, or because Moses interceded for them, or because God would glorify his own free mercy in sparing some, while he punished others, according to his declaration in a like case, Exodus 33:19. Hence the sons of Korah are mentioned 1 Chronicles 6:22,37, and oft in the book of Psalms.
Related Commentaries of Numbers 26:11
Numbers 26:11
11 Notwithstanding the children of Korah died not.