“angel of Yahweh appeared to him.” The angel was sitting under a tree. The idiom “appeared to him” likely does not mean that he popped in close to Gideon, but rather that Gideon noticed him. At this point Gideon did not know it was an angel, he thought it was a prophet sent by God. He discovered it was an angel when it burned up the offering and disappeared (Judg. 6:21-22).