Psalm 114:8

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 ) ( Numbers 20:11 ) ( Psalms 78:15 Psalms 78:16 ) ( 105:41 ) ( 1 Corinthians 10:4 ) .

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.