The messenger of YAHWEH sat under the oak of Gideon’s father Joash, and the following verses describe his appearance to Gideon and the conversation they had. The angel tells Gideon the message with which God had sent him.
Judges 6
12 And the messenger of YAHWEH appeared to him and said to him, “YAHWEH is with you, O mighty man!”
13 And Gideon said to him, “My lord, is YAHWEH with us? Why then has all this happened to us? And where are all His wonderful works which our fathers recounted to us, saying, ‘YAHWEH , didn’t He bring us up out of Egypt?’ And now YAHWEH has forsaken us and delivered us into the hands of Midian.”
14 Then YAHWEH turned to him and said, “Go in this might of yours and save Israel from the hand of Midian. Aren’t I sending you?”
mighty hero
Gideon is addressed by the angel as “mighty hero.” God points out to him what Gideon will be and what he will yet do. Just as God renamed Abram and changed his name to Abraham, meaning: father of many nations. Abram was childless and unable to produce life (Rom. 4:19), but God confirmed his promise of offspring to him by giving him a new name. So Gideon is already addressed here as a mighty hero.
this might of yours
Gideon, however, is not shy and asks where God is. True, God delivered His people from Egypt in the past, but now they are in the hand of Midian. Is the LORD with them?
The messenger’s answer is: go in this might of yours! What is this power? Is it Gideon’s testimony that he knew God had forsaken the people? Or does “this power” lie in the fact that Gideon is sent by God? In the latter case, “this power of yours” is the power that YAHWEH gives him, because He is the One who sends Gideon.
God’s Power
I think we don’t have to choose here, because both are possible. Gideon demonstrated his faith by knowing that Israel had forsaken God and therefore Israel was forsaken by God. After all, it was foretold in Scripture that it would happen this way.
But is it also God’s power in which he was sent: “Am I not sending you?” That will become clear later, when God ensures that all human glory is excluded and the large army that Gideon assembles is reduced to a group of 300 men, who defeat the enemy’s vast army with jars, torches, and ram’s horns.