He brought streams also out of the rock ... - literally, “flowings.” The waters were poured out in an over-flowing stream. Those streams continued to flow, thus constituting a continued proof of the presence of God. See this fully explained in the notes at 1 Corinthians 10:4.
Related Commentaries of Psalms 78:16
Psalms 78:16
16 He brought streams also out of the rock, and caused waters to run down like rivers.