The term itself refers to a course cloth made of goats’ hair. The cloth could be used for a sack or as a sieve or garment. It was considered too uncomfortable for daily usage and so was used only to express grief by the broken-hearted, be it in the face of the loss of a loved one or perhaps to convey repentance (see Genesis 37:34; Luke 10:13). John the Baptist wore camel’s hair in the vein of Elijah (Matthew 3:4; 2 Kings 1:8). It is tempting to claim that the garment of the two witnesses was the same material as John and Elijah used, and so suggest that these witnesses were an extension of Elijah and/or John the Baptist. But that would be going too far. It is better to understand that these witnesses feel the heavy boot of their oppressors and convey their hurt and humility in their attire. The significant thing, though, is that they continue to prophesy day by day despite their suffering.
3 And I will grant authority to my two witnesses, and they will prophesy for 1,260 days, clothed in sackcloth.”