Isaiah is speaking to the people of Judah.

## Strengthen the weak hands, and steady the knees that shake. ##

This represents a person who is fearful and despondent. (See: Metonymy)

## your God will come with vengeance, with the recompense of God ##

The words "vengeance" and "recompense" mean the same thing are are used together for emphasis. AT: “your God he will punish your enemies for what they did" (See: [[rc://en/ta/man/translate/figs-doublet]])