Why did Moses pray, "God of all Spirits of all flesh" when requesting a new leader for Israel? Rashi explains that Moses said to the LORD, "Master of the Universe! The personality of every human is revealed before you, and you know that no two are exactly alike. Appoint a leader over them that will bear with each one according to his personality."
The LORD answered Moses' prayer for a successor by appointing Joshua, the servant of Moses, as the next leader of Israel. Joshua was a man in whom the Spirit of God resided.
How did Joshua become such a great and worthy leader? He learned the art of leadership by being a careful disciple and faithful servant of Moses. If a person desires to develop in wisdom, he should spend time with the wise. If a person desires to develop in righteousness, he should spend time with righteous people. If a person desires to become a good leader, he should stay close to good leaders. Likewise, as we become better disciples of our teacher Yeshua of Nazareth, we will become more and more like Him. The Gospel of Luke says, "A pupil is not above his teacher; but everyone, after he has been fully trained, will be like his teacher" (Luke 6:40).
The LORD told Moses to lay his hands on Joshua, symbolizing a transfer of authority and spiritual prowess. The laying-on-of-hands ritual signifies an investment of identity. For example, when a person bringing a sacrifice laid his hands on the animal's head, he was investing the animal with his own identity so the animal could represent him before God:
He shall lay his hand on the head of the burnt offering, that it may be accepted for him to make atonement on his behalf. (Leviticus 1:4)
Moses laid his hands on Joshua in front of all Israel so there would not be any question about who was designated to succeed him. He endowed Joshua with his authority so the Israelites would obey him. Rashi says that, just as Moses' face shone like the sun because of his encounters with the presence of God, Joshua's face glowed like the moon after Moses laid hands upon him. The Midrash Rabbah, an ancient collection of rabbinic commentary on the Torah, likens Moses' laying his hands on Joshua to one candle lighting another:
Like one who lights one candle with another, [the leaders of Israel] were filled with the Holy Spirit. They were filled with the Holy Spirit taken from the spirit of Moses, but the Spirit of Moses was not diminished. This is like the case of a man who lights one candle with another. The one candle ignites but the flame on the other candle is not diminished. (Numbers Rabbah 21:15; 13:20)
The transfer of the Holy Spirit from Moses to his disciple Joshua enables us to better understand why the disciples of Yeshua were invested with the Holy Spirit after His ascension. In the same way that Joshua was to take on the mantle of Moses after his departure, the disciples of Yeshua are responsible for carrying on His work.