Charles Ellicott Commentary Exodus 17:5

"And Jehovah said unto Moses, Pass on before the people, and take with thee of the elders of Israel; and they rod, wherewith thou smotest the river, take in thy hand, and go." — Exodus 17:5 (ASV)

Go on before the people. — The people were probably in no condition to move. They were exhausted with a long day’s march—weary, faint, and nerveless. Moses and the elders, who probably journeyed on donkeys, would have more strength.

Take with you of the elders — as witnesses. Each miracle had an educational value and was designed to call forth, exercise, and so strengthen the faith of the people.

The rock in Horeb must necessarily designate some particular rock in the Horeb region already known to Moses during his previous stay in this area. It cannot possibly, however, have been the traditional “rock of Moses” in the Seil Leja, under Ras Sufsafeh, since that rock is a long day’s journey from the site of Rephidim, near which the miracle must have been performed. (See Stanley, Sinai and Palestine, pp. 46-48.)