I say the Holy Spirit.
Exodus 3:15
God also said to Moses, “Say to the Israelites, ‘The Lord, d the God of your fathers—the God of Abraham, the God of Isaac and the God of Jacob—has sent me to you.’
John 16:13
But when he, the Spirit of truth, comes, he will guide you into all the truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come
Would not the holy spirit be the holy spirit?. The same one from the Tanahk doing the same job it did through the prophet's just on a larger scale since the day of pentacost.
Moses and Aaron
Peter and Andrew
Both had brothers who sought after them when G-d called:
Aaron sought Moses at Mt. Horeb's desert
Andrew went to find Peter (John 1: 41)
Both "shepherds" of G-d's people:
Moses shepherd for forty years watching father-in-laws sheep.
Peter a fisherman called to become shepherd of Christians. ("Feed my sheep.")
Both had a miracle associated with their introduction to G-d:
Miraculous fire in burning bush
Called with miraculous catch of fish
Both had a miraculous fire associated with their call to lead G-d's people:
Called by angel in burning bush
Tongues of fire come upon him
Both called to go before secular leaders in behalf of G-d's people:
Called to go before Pharaoh
Witness before governors and kings (Matt. 10:18)
Both recoiled from G-d's presence at first:
Moses said, "Who am I, that I should go before Pharaoh?" (Ex. 3: 11)
Peter fell at Jesus feet and said, "Go away from me, Lord; I am a sinful man!" (Luke 5:8)
Both men represented G-d to the people and the world:
G-d told Moses that Aaron, "will speak to the people for you, and it will be as if he were your mouth and as if you were G-d to him." And, "Then the LORD said to Moses, 'See, I have made you like G-d to Pharaoh, and your brother Aaron will be your prophet.' "(Ex. 4: 16; 7:1)
G-d told Peter, "And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will beloosed in heaven." (Matt. 16:18, 19)
Both calls were in the context of understanding who G-d was, the "I AM."
Moses asked G-d's name and He responded, "I AM, who I AM."
Jesus asked Peter "Who do you say that I AM?" And Peter's answer proved he understood who Christ was. Both were given authority upon the name of the Great I AM.
After being commissioned, both were immediately rebuked:
Both publicly betrayed G-d:
Moses by hitting the rock
Peter by denying Him three times
Both were given the ability to perform signs and wonders!