Joel 2:31

The sunlight will be turned to darkness and the moon to the color of blood, ¹  before the day of the Lord comes – that great and terrible day!

Isa 13:9,10; Isa 34:4,5; Joe 2:10; Joe 3:1,15; Zep 1:14-16; Mal 4:1,5; Mt 24:29; Mt 27:45; Mr 13:24,25; Lu 21:25; Re 6:12,13

¹ tn Heb “to blood,” but no doubt this is intended to indicate by metonymy the color of blood rather than the substance itself. The blood red color suggests a visual impression here – something that could be caused by fires, volcanic dust, sandstorms, or other atmospheric phenomena.