en_tn/jer/21/05.md

Then I myself

This is emphatic and stresses that Yahweh is the one who will do this. (See: rc://en/ta/man/jit/figs-rpronouns)

with a raised hand and a strong arm

Both of these phrases are idiomatic expressions that refer to great power. Alternate translation: "with very great power" (See: rc://en/ta/man/jit/figs-idiom and rc://en/ta/man/jit/figs-doublet)

with wrath, fury, and great anger

These words all mean basically the same thing. Together they emphasize the great intensity of his anger. Alternate translation: "with extremely great anger" (See: rc://en/ta/man/jit/figs-doublet)