And Moses said unto him, Enviest thou for my sake? would God that all the LORD's people were prophets, and that the LORD would put his spirit upon them!

Wesley's Notes

11:29 Enviest thou for my sake - Art thou grieved because the gifts and graces of God are imparted to others besides me? Prophets - He saith prophets, not rulers, for that he knew was absurd and impossible. So we ought to be pleased, that God is glorified and good done, tho' to the lessening of our own honour.

Matthew Henry's Concise Commentary

11:24-30 We have here the fulfilment of God's word to Moses, that he should have help in the government of Israel. He gave of his Spirit to the seventy elders. They discoursed to the people of the things of God, so that all who heard them might say, that God was with them of a truth. Two of the elders, Eldad and Medad, went not out unto the tabernacle, as the rest, being sensible of their own weakness and unworthiness. But the Spirit of God found them in the camp, and there they exercised their gift of praying, preaching, and praising God; they spake as moved by the Holy Ghost. The Spirit of God is not confined to the tabernacle, but, like the wind, blows where He listeth. And they that humble themselves shall be exalted; and those who are most fit for government, are least ambitious of it. Joshua does not desire that they should be punished, but only restrained for the future. This motion he made out of zeal for what he thought to be the unity of the church. He would have them silenced, lest they should occasion a schism, or should rival Moses; but Moses was not afraid of any such effects from that Spirit which God had put upon them. Shall we reject those whom Christ has owned, or restrain any from doing good, because they are not in every thing of our mind? Moses wishes all the Lord's people were prophets, that he would put his Spirit upon all of them. Let the testimony of Moses be believed by those who desire to be in power; that government is a burden. It is a burden of care and trouble to those who make conscience of the duty of it; and to those who do not, it will prove a heavier burden in the day of account. Let the example of Moses be followed by those in power; let them not despise the advice and assistance of others, but desire it, and be thankful for it. If all the present number of the Lord's people were rendered prophets, or ministers, by the Spirit of Christ, though not all agreed in outward matters, there is work enough for all, in calling sinners to repentance, and faith in our Lord Jesus.