en_tn/isa/30/29.md

Isaiah continues speaking to the people of Judah.

when a holy feast is observed

AT: "when you observe a holy feast" (See: rc://en/ta/man/translate/figs-activepassive)

and gladness of heart

"and you will be glad"

flute

See how you translated this in Isaiah 5:11.

to the Rock of Israel

This refers to Yahweh and compares him to a rock because he protects his people. AT: "Israel's protective rock" or "who is like a protective rock for Israel."