en_tn_lite_do_not_use/isa/53/01.md

Here Isaiah describes events that will happen in the future as if they happened in the past. This emphasizes that they certainly will happen.

Who would have believed what we heard?

What Isaiah just found out is so amazing that he wonders if the exiles will believe it. The "we" includes him and those in exile. (See: rc://en/ta/man/translate/figs-inclusive and rc://en/ta/man/translate/figs-rquestion)

Who would have believed

This question is like the one above, expressing surprise.

And the arm of Yahweh, to whom was it revealed?

AT: "And to whom has Yahweh revealed his power?" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-activepassive)

For he grew up before Yahweh like a sapling, and like a sprout out of parched earth

Here "he" refers to God's servant whom Isaiah compares to a very young tree. This emphasizes that he will appear weak. (See: rc://en/ta/man/translate/figs-simile)