Joel 2:31

The sun shall be turned into darkness - The Jewish polity, civil and ecclesiastical, shall be entirely destroyed.

Before the great and the terrible day of the Lord come - In the taking and sacking of Jerusalem, and burning of the temple, by the Romans, under Titus, the son of Vespasian. This was, perhaps, the greatest and most terrible day of God's vengeance ever shown to the world, or that ever will be shown, till the great day of the general judgment. For a full view of this subject, I wish to refer the reader to the notes on Matthew 24.

Before the great and terrible Day of the Lord come - o: "The days of our life are our days wherein we do what we please; that will be the "Day of the Lord," when He, our Judge, shall require the account of all our doings. It will be "great," because it is the horizon of time and eternity; the last day of time, the beginning of eternity. It will put an end to the world, guilt, deserts, good or evil. It will be "great," because in it great things will be done. Christ with all His Angels will come down and sit on His Throne; all who have ever lived or shall live, shall be placed before Him to be judged; all thoughts, words, and deeds shall be weighed most exactly; on all a sentence will be passed, absolute, irrevocable throughout eternity; the saints shall be assigned to heaven, the ungodly to hell; a great gulf shall be placed between, which shall sever them forever, so that the ungodly shall never see the godly nor heaven nor God; but shall be shut up in a prison forever, and shall burn as long as heaven shall be heaven, or God shall be God." : "That day shall be great to the faithful, terrible to the unbelieving; great to those who said, 'Truly this is the Son of God;' terrible to those who said, 'His blood be upon us and upon our children.'" : "When then thou art hurried to any sin, think on that terrible and unendurable judgment-seat of Christ, where the Judge sits on His lofty Throne, and all creation shall stand in awe at His glorious Appearing and we shall be brought, one by one, to give account of what we have done in life. Then by him who hath done much evil in life, there will stand terrible angels. "There" will be the deep gulf, the impassable darkness, the lightless fire, retaining in darkness the power to burn, but reft of its rays. There is the empoisoned and ravenous worm insatiably devouring and never satisfied, inflicting by its gnawing pangs unbearable. There that sharpest punishment of all, that shame and everlasting reproach. Fear these things; and, instructed by this fear, hold in thy soul as with a bridle from the lust of evil."

2:31 The sun - Having mentioned the prodigies which were to be wrought on earth, he now specifies what shall be done in heaven.The terrible day - The unholy day of the destruction of Jerusalem; typifying the day of judgment.