en_tn/isa/08/06.md

Because this people has refused the gentle waters of Shiloah

The words "gentle waters" are a metaphor for the law of the Lord. Alternate translation: "Because this people has rejected Yahweh's law, which is like the gentle waters of Shiloah" (See: rc://en/ta/man/jit/figs-metaphor and rc://en/ta/man/jit/translate-names)

this people

"this people group." If your language needs a plural here, you can translate this phrase and the following verbs as "these people have refused ... are happy."

is happy over Rezin and Remaliah's son

The full meaning can be made explicit. See how you translated these men's names in Isaiah 7:1. Alternate translation: "is happy that the armies of Assyria have defeated Rezin, king of Aram, and Pekah, Remaliah's son, king of Israel" (See: rc://en/ta/man/jit/figs-explicit)