Which turned the rock into a standing water - That is, Before him who could do this, the earth should tremble; the inhabited world should stand in awe of such amazing power. The words rendered "a standing water," mean properly a pool of water. They indicate nothing in regard to the permanency of that pool; they do not imply that it remained as a standing pool during the sojourn of the Israelites in the wilderness - whatever may have been the fact in regard to that. The simple idea is, that, at the time referred to, the rock was converted into a pool; that is, the waters flowed from the rock, constituting such a pool.
The flint - Another name for the rock - used here to describe the greatness of the miracle.
Into a fountain of waters - That is, The waters flowed from the rock as from a fountain. The Bible is a book of miracles, and there is nothing more improbable in this miracle than in any other.
In the Septuagint, the Latin Vulgate, the Syriac, the Arabic, and in many manuscripts, there is no division of the psalm here, but the following psalm is united with this, as if they were a single poem. Why, in those versions, the division of the Hebrews. was not followed, cannot now be ascertained. The division in the Hebrew is a natural division, and was evidently made in the original composition.

The flint - I have translated חלמיש challamish, Granite; for such is the rock of Horeb, a piece of which now lies before me.
This short and apparently imperfect Psalm, for elegance and sublimity, yields to few in the whole book.
It is so well translated in the old Psalter, that I think I shall gratify the reader by laying it before him.
Psalm 114:1 In gangyng of Isrel oute of Egipt,Of the house of Jacob fra hethen folke.
Psalm 114:2 Made is Jude his halawyngIsrel might of hym.
Psalm 114:3 The se sawe and fled,Jurdan turned is agayne;
Psalm 114:4 Hawes gladed als wethers,And hilles als lambes of schepe.
Psalm 114:5 What is to the se, that thou fled?And thou Jordane that thou ert turned agayne?
Psalm 114:6 Hawes gladded als wethers?And hils als lambs of schepe.
Psalm 114:7 Fra the face of Lorde styrde is the erth,Fra the face of God of Jabob;
Psalm 114:8 That turnes the stane in stank of waters,And roche in wels of waters.
And, as a still more ancient specimen of our language, I shall insert the Anglo-Saxon, with a literal reading, line for line, as near to the Saxon as possible, merely to show the affinity of the languages.
Psalm 114:1 On outgang Israel of Egypt,House Jacob of folk foreigners;
Psalm 114:2 Made is Jacob holyness his;Israel andweald (government) his.
Psalm 114:3 Sea saw, and flew!Jordan turned underback!
Psalm 114:4 Mounts they fain (rejoiced) so (as) rams,And burghs (hillocks) so (as) lamb - sheep.
Psalm 114:5 What is the sea, that thou flew?And thou river for that thou turned is underback?
Psalm 114:6 Mounts ye fained (rejoiced) so so rams;And hills so so lambs - sheep.
Psalm 114:7 From sight Lord's stirred is earth;From sight God of Jacob.
Psalm 114:8 Who turned stone in mere waters;And cliffs in wells waters.
I have retained some words above in nearly their Saxon form, because they still exist in our old writers; or, with little variation, in those of the present day: -
Psalm 114:2 Andweald, government. Hence weal and wealth, commonweal or wealth; the general government, that which produces the welfare of the country.
Psalm 114:4 Faegnodon, fained - desired fervently, felt delight in expectation.
Psalm 114:4 Burgh, a hill - a mound or heap of earth, such as was raised up over the dead. Hence a barrow; and hence the word bury, to inhume the dead.
Psalm 114:8 Mere, or meer, a large pool of water, a lake, a lough, still in use in the north of England. Gentlemen's ponds, or large sheets of water so called; and hence Winander-mere, a large lake in Westmoreland. Mere also signifies limit or boundary; hence the Mersey, the river which divides Lancashire from Cheshire, and serves as a boundary to both counties. The mere that spreads itself out to the sea.
Instead of cludas, which signifies rocks, one MS. has clyf, which signifies a craggy mountain or broken rock.
The reader will see from this specimen how much of our ancient language still remains in the present; and perhaps also how much, in his opinion, we have amplified and improved our mother tongue.

Which (e) turned the rock [into] a standing water, the flint into a fountain of waters.
(e) That is, miraculously caused water to come out of the rock in great abundance, (Exodus 17:6).

Which turned the rock into a standing water,.... Both at Rephidim and at Kadesh; which being smitten, streams of water flowed out like rivers, as if the rock itself was changed into water; and which came a constant and continual supply for the Israelites, for it is said to follow them; see Exodus 17:6.
The flint into a fountain of waters; referring to the same thing, the rocks were flinty ones. This was a type of Christ the Rock; who has an abiding fulness of grace in him; is the fountain of it, from whence it flows in great abundance for the supply of his people's wants, while passing through this wilderness to Canaan's land.