Jamieson, Fausset & Brown

rush--rather, "paper-reed": The papyrus of Egypt, which was used to make garments, shoes, baskets, boats, and paper (a word derived from it). It and the flag, or bulrush, grow only in marshy places (such as are along the Nile). So the godless thrives only in external prosperity; there is in the hypocrite no inward stability; his prosperity is like the rapid growth of water plants.