Numbers 27:18

Take thee Joshua, the son of Nun— Hence it appears, that this high office of leader or judge of Israel was not to be hereditary; nor did the policy of Moses take one step to perpetuate it in his own posterity or family; a convincing proof of his disinterestedness, and one which shews him to have been actuated by a principle which raised him above other lawgivers, who generally took care to advance their own families. As it was necessary that this office should be discharged by a person of the most eminent qualifications, God therefore appoints Joshua, the son Nun, who had been a constant attendant upon Moses, but who was of another family, and another tribe. He is said to be a man in whom is the spirit; respecting which, see Genesis 41:38. Exodus 28:3 and Deuteronomy 34:9.

And lay thine hand upon him— The ceremony of laying on of hands denoted Moses's transferring the public trust delegated to him from God, upon Joshua, from himself. This ceremony was accompanied with solemn prayer, for the influence of the Divine Spirit to qualify the party for his office; and, when performed by men endued with a prophetic spirit, as Moses and the apostles, it was a sign and attestation of those moral endowments which God was pleased to convey to him who was thus invested with an office. See Deuteronomy 34:9. 1 Timothy 4:14. 2 Timothy 1:6 and Le Clerc on the passage.