Augustine of Hippo : the Church, shall be darkened, because in those tremendous temptations and tribulations which shall be in the end of the world, many who had seemed as bright and as firm as the sun and the stars shall fall from the faith. Basil of Caesarea : these are the signs of the end of the world. Bede : The sun shall be turned into darkness, and the moon into blood. This is believed to have been partly fulfilled during the Lord's Passion, and partly to occur before the great day, that is, the Day of Judgment. For at that time the sun was darkened, but the moon, turned into blood, could not plainly appear to men, since it was (as it happens during Passover) the fifteenth day, and during the day it was hidden from mortal sight by the obstruction of the earth. — Commentary on Acts Bede : The sun will be turned into darkness. The name of darkness in Greek is read in the singular number, that is, σκότος, which the Latin translator necessarily rendered in the plural as tenebras because he could not express it in the singular. I thought it necessary to mention this so that anyone who reads this among the people of the Angles might know that it is not necessary, because of the authority of the Latin language, to render "darkness" in their own speech in the plural; rather, it should be in the singular, as this can just as easily be done owing to the authority of the Greek, from which it was translated into Latin scripture. — Retractions on Acts Hippolytus of Rome : For at that time the trumpet shall sound, and awake those that sleep from the lowest parts of the earth, righteous and sinners alike. And every kindred, and tongue, and nation, and tribe shall be raised in the twinkling of an eye; and they shall stand upon the face of the earth, waiting for the coming of the righteous and terrible Judge, in fear and trembling unutterable. For the river of fire shall come forth in fury like an angry sea, and shall burn up mountains and hills, and shall make the sea vanish, and shall dissolve the atmosphere with its heat like wax. The stars of heaven shall fall, the sun shall be turned into darkness, and the moon into blood. The heaven shall be rolled together like a scroll: the whole earth shall be burnt up by reason of the deeds done in it, which men did corruptly, in fornications, in adulteries, and in lies and uncleanness, and in idolatries, and in murders, and in battles. For there shall be the new heaven and the new earth. — Dubious and Spurious Pieces John Chrysostom : "Before that great and notable day of the Lord come." For be not confident, he means to say, because at present you sin with impunity. For these things are the prelude of a certain great and dreadful day. Do you see how he made their souls to quake and melt within them, and turned their laughter into pleading for acquittal? For if these things are the prelude of that day, it follows that the extreme of danger is impending. — Homily on Acts 5