Joel 2:31

The sun shall be turned into darkness, being changed into a dark and cold mass, and the moon into blood, as bloody wars and devastations would occur on the earth, before the great and the terrible Day of the Lord come, namely, the day of the final Judgment. Cf 1 Thessalonians 5:2; 1 Corinthians 1:8; 2 Corinthians 1:14; 2 Thessalonians 2:8.