Albert Barnes Commentary Numbers 27:16

"Let Jehovah, the God of the spirits of all flesh, appoint a man over the congregation," — Numbers 27:16 (ASV)

The God of the spirits of all flesh - An acknowledgment that man, who is but flesh , is of himself helpless; and lives and moves and has his being in God (Acts 17:28). The words are suitably employed here to introduce an entreaty that God would not leave the congregation without a guide and leader, and in Numbers 16:22 as a preface to an intercession that the whole people should not suffer for the sin of a few.