The Pulpit Commentary - Exodus 17:6
Behold, I will stand before thee there. A visible Divine appearance seems to be intended, which would guide Moses to the exact place where he should strike. The rock in Horeb must have been a remarkable object, already known to Moses during the time that he dwelt in the Sinai-Horeb region; but its exact locality cannot be pointed out. It cannot, however, have been very far distant from Rephidim. (See Exodus 17:8 .) read more
The Pulpit Commentary - Exodus 17:5
Go on before the people. "Leave the people," i.e; "where they are, in Rephidim, and go on in front of them, with some of the elders as witnesses, that the miracle may be sufficiently attested." On the other occasion, when water was brought forth out of the rock ( Numbers 20:8-11 ), it was done in the presence of the people. Perhaps now there was a real danger of their stoning Moses, had he not quitted them. Thy rod with which thou smotest the river. See above, Exodus 7:20 . read more