And it shall come to pass in that day, saith the Lord GOD, that I will cause the {g} sun to go down at noon, and I will darken the earth in the clear day:

(g) In the midst of their prosperity, I will send great affliction.

Wesley's Notes

8:9 At noon - So Israel's sun did as at noon set under the dark cloud of conspiracies and civil wars by Shallum, Menahem, Pekah, and Hosea, 'till the midnight darkness drew on by Pul, Tiglath - Pilneser, and Salmaneser. Darken - Bring a thick cloud of troubles and afflictions. In the clear day - When they think all is safe, sure, and well settled.

Jamieson-Fausset-Brown Bible Commentary

9. "Darkness" made to rise "at noon" is the emblem of great calamities (Jer 15:9; Eze 32:7-10).

Matthew Henry's Concise Commentary

8:4-10 The rich and powerful of the land were the most guilty of oppression, as well as the foremost in idolatry. They were weary of the restraints of the sabbaths and the new moons, and wished them over, because no common work might be done therein. This is the character of many who are called Christians. The sabbath day and sabbath work are a burden to carnal hearts. It will either be profaned or be accounted a dull day. But can we spend our time better than in communion with God? When employed in religious services, they were thinking of marketings. They were weary of holy duties, because their worldly business stood still the while. Those are strangers to God, and enemies to themselves, who love market days better than sabbath days, who would rather be selling corn than worshipping God. They have no regard to man: those who have lost the savour of piety, will not long keep the sense of common honesty. They cheat those they deal with. They take advantage of their neighbour's ignorance or necessity, in a traffic which nearly concerns the labouring poor. Could we witness the fraud and covetousness, which, in such numerous forms, render trading an abomination to the Lord, we should not wonder to see many dealers backward in the service of God. But he who thus despises the poor, reproaches his Maker; as it regards Him, rich and poor meet together. Riches that are got by the ruin of the poor, will bring ruin on those that get them. God will remember their sin against them. This speaks the case of such unjust, unmerciful men, to be miserable indeed, miserable for ever. There shall be terror and desolation every where. It shall come upon them when they little think of it. Thus uncertain are all our creature-comforts and enjoyments, even life itself; in the midst of life we are in death. What will be the wailing in the bitter day which follows sinful and sensual pleasures!