So, why are John’s clothes described? Several reasons, starting with John channeling Elijah the prophet’s dress in the Old Testament. Elijah rebuked sin and was prepared to lead the way for the people of Israel to return to the Lord:
“He wore a garment of haircloth, with a girdle of leather about his loins.” And he said, ‘It is Elijah the Tishbite’” (2 Kings 1:8). Later in Matthew’s gospel, when John was in prison, Jesus spoke about the Elijah connection to John’s followers:
"Truly, I say to you, among those born of women there has risen no one greater than John the Baptist ... and if you are willing to accept it, he is Elijah who is to come" (Matthew 11:11) and (Matthew 11:14). And shortly before that: