Gevurot Meyruach Hakodesh 1:9-10

And having said these things, while they were looking on, in an aliyah ascent to Shomayim, Moshiach was taken up; and an anan (cloud) took him away from their eyes. And as they were gazing intently into Shomayim, while Moshiach was going — hinei — two beings, enrobed in white, had been present with them.