John Gill Commentary Judges 6:36

"And Gideon said unto God, If thou wilt save Israel by my hand, as thou hast spoken," — Judges 6:36 (ASV)

And Gideon said to God
Not to a prophet of God who was there, of whom he asked the following signs to be done, as Ben Gersom, but to God in prayer, as Abarbinel:

if you will save Israel by my hand, as you have said ;
not that he doubted of it, but was willing to have a confirmation of his faith; and perhaps his view was more for the encouragement of those that were with him than himself, that he desired the following signs; and though he had had one before, that was to show that he was truly an angel that spoke to him, and not to ascertain the salvation that should be wrought by him; though that might be concluded from his being an angel that spoke to him, and assured him of it.