en_tn_condensed/isa/58/05.md

Is this really the kind of fast that I would want ... under himself?

Yahweh uses a question to scold the people. They act like they are humble before God, but they are hurting other people. Alternate translation: "This is not the kind of fast I want ... under himself." (See: rc://en/ta/man/translate/figs-rquestion)

A day for anybody to humble himself, for him to bow down his head like a reed

This means the person is bowing down, but he is not truly humble. "A reed" represents a weak plant that bends easily. (See: rc://en/ta/man/translate/figs-simile)

Do you really call this a fast, a day that pleases Yahweh?

Yahweh uses a question to scold the people. Alternate translation: "Surely you do not think this kind of fast pleases me!" (See: rc://en/ta/man/translate/figs-rquestion)