There is another man who wore similar clothing in the Scriptures, one who lived many centuries before John’s birth. To this man the angel of the Lord said:
Go, intercept the messengers of Samaria’s king, and ask them, ‘Is it because there is no God in Israel that you are going to inquire of Baalzebub, the god of Ekron?’ For this, the Lord says: ‘You shall not leave the bed upon which you lie; instead, you shall die’” (II Kings 1:3-4).Hearing these words, the king’s messengers returned to him. King Ahaziah asked them, “What was the man like who came up to you and said these things to you” (II Kings 1:7). “‘Wearing a hairy garment,’ they replied, ‘with a leather girdle about his loins’” (II Kings 1:8). Hearing this description, the king knew at once the name of this name and cried out, “It is Elijah the Tishbite” (II Kings 1:8)!
By donning a garment made of camel’s hair and securing it with a belt of leather, John the Baptist demonstrated in a clear way his prophetic calling. We learn through the prophet Zechariah that this form of dress was customary for the prophets: “On that day, every prophet shall be ashamed to prophesy his vision, neither shall he assume the hairy mantle: (Zechariah 13:4). But more than this, John showed through the use of his clothing, that he was Elijah.
The grandson of the wise Sirach wrote, “How awesome are you, Elijah! Whose glory is equal to yours” (Sirach 48:10)? Furthermore, he said to him,
You are destined, it is written, in time to come to put an end to wrath before the day of the Lord, to turn back the hearts of fathers toward their sons, and to re-establish the tribes of Jacob. Blessed is he who shall have seen you before he dies, O Elijah, enveloped in the whirlwind (Sirach 48:10-12)!Sirach references and quotes the words of the Prophet Malachi:
Lo, I will send you Elijah, the prophet, before the day of the Lord comes, the great and terrible day, to turn the hearts of the fathers to their children, and the hearts of the children to their fathers, lest I come and strike the land with doom (Malachi 3:24).So much so did John the Baptist’s life reflect that of Elijah, Jesus said of John:
All the prophets and the law prophesied up to the time of John. And if you are willing to accept it, he is Elijah, the one who is to come. Whoever has ears ought to hear (Matthew 11:13-15).Saint John Chrysostom tells us, “John’s clothing itself was symbolic of nothing less than the coming kingdom and of repentance.”
 Saint John Chrysostom, The Gospel of Matthew, Homily 10.4.