"And whoever punishes with the equivalent of that with which he was punished and then is oppressed," meaning: the polytheists of the Arabs, for they were punished, and Allah destroyed them for their denial of the Prophet, their oppression of him and his companions, and their transgression against them. "Allah will surely aid him," where victory in this world means triumph over the polytheists, and in the Hereafter, it means the compelling proof against them.