Isaiah 16:5

And in mercy If we follow Hitzig's view of Isaiah 16:4 this would be rendered "then in mercy." The phraseology of the verse is Messianic (see esp. ch. Isaiah 9:6) but not exclusively so (cf. Proverbs 8:28). In the lips of the Moabites the language is that of extravagant and (as Isaiah 16:6 appears to intimate) insincere adulation. It implies an offer of perpetual submission on the part of the Moabites to the Davidic dynasty, and therefore the question whether the throne be that of Judah or that of Moab is immaterial.

and he shall sit … judging Better: and there shall sit upon it in faithfulness in the tabernacle of David (cf. Amos 9:11) one who judgeth, &c.

hasting righteousness i.e. as R.V. has it, swift to do righteousness.