Literally, this did Jesus again as a second sign. The pleonasm in again, the second, is only apparent. Other miracles had indeed been wrought between these two; but John emphasizes these two as marking Jesus' coming from Judaea to Galilee. The healing of the nobleman's child was the second miracle, only in respect of its taking place upon Jesus' withdrawal from Judaea into Galilee. Hence the again. He wrought a miracle again, when He again came into Galilee, and this miracle was the second, as marking His second coming.