Jeremiah 2:13 - Ellicott's Commentary On The Whole Bible

The fountain of living waters. — The word rendered “well,” as in Proverbs 10:11; Proverbs 18:4; “fountain,” as in Psalms 36:9, is used of water flowing from the rock. The “cistern,” on the other hand, was a tank for surface water. A word identical in sound and meaning, though differently spelt, is variously rendered by “pit,” “well,” or “cistern.”