‘ And Gideon said to God, “If you will save Israel by my hand, as you have said.” '
Gideon is about to ask another sign. Note that the request is made to ‘God', not Yahweh, and thus continues through the section. There is a hint here that the request was seen as not strictly pleasing, for Gideon had admitted that Yahweh had said that He would save Israel by his hand. There should therefore be no need to require a further sign from the covenant God, from Yahweh. So this was a personal thing between Gideon and God. It was nothing to do with the covenant.
But God was patient, for this was no hardened warrior, this was a young man in the making who through most of his manhood had known only times of oppression (and whose brothers had been murdered by these very raiders when resisting). The writer may have had in mind Deuteronomy 6:16, compare Exodus 17:7, where ‘Yahweh' was not to be put to the test.