What kind of spiritual leadership would the seventy men have?
The seventy men would receive the same qualities of spiritual leadership Moses had, because God would take of the Spirit upon Moses and put it upon them. They would be divinely empowered to bear the burden of the people with Moses, rather than relying on natural, fleshly advice like Jethro's.
Les explains that God told Moses He would come down and talk with him, take of the Spirit upon Moses, and put it upon the seventy. They would bear the burden of the people with Moses so he would not bear it alone. This was spiritual empowerment, unlike Jethro's earlier advice, which was a high moral example but natural, of the flesh. God said He would give these seventy men the power, enabling them to have the same qualities of spiritual leadership Moses had from the beginning. Moses let his father-in-law depart after taking his advice for what it was worth, which wasn't much, and soon God revealed His way.
And I will come down and talk with thee there: and I will take of the spirit which is upon thee, and will put it upon them; and they shall bear the burden of the people with thee, that thou bear it not thyself alone.
More Questions
Was Jethro's advice spiritual or fleshly?
Jethro's advice, though a high moral example, was natural and of the flesh, and did not include the spiritual empowerment God later provided.