undo - Maurer translates, “I will deal with,” that is, as they deserve. Compare Eze 23:25, where the Hebrew is similarly translated. The destruction of Israel’s foes precedes Israel’s restoration (Isa 66:15, Isa 66:16).
her that halteth - all that are helpless. Their weakness will be no barrier in the way of My restoring them. So in Psa 35:15, Margin, “halting” is used for adversity. Also Eze 34:16; Mic 4:6, Mic 4:7.
I will get them praise, etc. - literally, “I will make them (to become) a praise and a name,” etc.