I clothe the heavens with blackness,.... With gross and thick darkness; perhaps referring to the three days' darkness the Egyptians were in, Ex 10:12, or with thick and black clouds, as in tempestuous weather frequently; or by eclipses of the sun; there was an extraordinary instance of great darkness at the time of Christ's crucifixion, Mt 27:45and I make sackcloth their covering; that being black, and used in times of mourning; the allusion may be to the tents of Kedar, which were covered with sackcloth, or such like black stuff.
The fall of the Pagan empire, through the power of Christ and his Gospel, is signified by the sun becoming black as sackcloth of hair, Re 6:12.