Isaiah 58:8 - Joseph Benson’s Commentary on the Old and New Testaments

Then shall thy light Matter or cause of rejoicing, break forth as the morning Arise as certainly and speedily as in the morning the light arises out of darkness. It shall not only appear, but break, or dart itself forth, notwithstanding all obstructions, as the sun breaks and pierces through a cloud. So ready is God to help his people when they are truly humbled! Thus quickly and clearly does salvation break forth upon them! And thy health shall spring forth speedily The recovery of thy former prosperous condition. Another metaphor to express the same thing. And thy righteousness shall go before thee To prepare thy way to safety and happiness; ensuring to thee, O my church, the peculiar direction and care of thy God, and the favour and approbation of wise and good men; see Romans 14:17-18. Or manifold blessings shall be bestowed upon thee, upon all occasions, as the reward of thy righteousness. The glory of the Lord shall be thy rereward The glorious presence, power, and providence of God shall protect and secure thee. Thus the angel of his presence secured the Israelites when they came up out of Egypt. Or, the meaning may be, A glorious state shall succeed this thy present calamitous condition.