When looked at in its entirety, the Christian Bible is broken up into the Old and New Testaments. We have a general understanding of the role of each Testament (Old is the story of Israel and New is the story of Christianity), but rarely do we pay attention to the transition from Old to New. The very last words of the Old Testament come from the short book of Malachi:

“Now I am sending to you Elijah the prophet, Before the day of the Lord comes, the great and terrible day; He will turn the heart of fathers to their sons, and the heart of sons to their fathers, Lest I come and strike the land with utter destruction.” (Malachi 3:23-24)

Immediately following this passage are the Gospels. All four Gospels clearly mention the role of John the Baptist as the one who prepares the way for the Lord. Throughout the Gospels and Christian tradition, John the Baptist is regularly linked with the ancient prophet Elijah. Although we read that John denies that he is Elijah in the Gospel of John, Jesus asserts that he in fact is in the Gospel of Matthew: 

“And if you are willing to accept it, he is Elijah, the one who is to come.” (Matthew 11:14)

Although there are simple comparisons between the two (Both wore clothing fit for life in the wilderness, and both preached a strict message of penance and repentance), John carries on the role of Elijah in the New Testament, while uniting the Old and New Testaments seamlessly.