Shiloah: i.e. the waters beneath Zion running from Gihon to Siloam. See App-68.
rejoice in Kezin. This is not "a wrong reading of the Hebrew text", hut it refers to the trust reposed in the king of Syria instead of in Jehovah (Isaiah 7:9). They despised God's covenant with Zion (symbolized by its secret stream), and preferred the help of the heathen; therefore the Assyrian floods should overwhelm them. (Compare the same contrast in Psalms 46:3, Psa 46:45. and see notes there.) This applied specially to Israel: and the judgment overtook Israel first.