For they were departed from Rephidim,.... After they had fought with Amalek, and came to the western part of the mount to Horeb, where the rock was smitten for them; and they were come from that now, and encamped at Sinai, after Jethro had paid a visit to Moses:and were come to the desert of Sinai, and had pitched in this wilderness; that is, of Sinai, as in the preceding verse:and there Israel encamped before the mount; Mount Sinai, from whence the desert or wilderness was called.
This, as Jarchi says, was on the east side of the mount; Horeb and Sinai were but one and the same mountain, which had two tops. Horeb was on the western side, near to which lay the plain of Rephidim; and Sinai was on the eastern side, on which the wilderness of that name bordered: so that the children of Israel, when they came from Rephidim, came from the western side, and took a circuit about and came to the eastern; which, according to a fore mentioned writer, was eight miles, and was the twelfth station or mansion of the children of Israel.