Malachi 4:5
5 Behold, I will send you Elijah the prophet before the great and terrible day of Yahweh comes.
Elijah was one of Israel's most prominent prophets. He confronted idolatry, challenged corrupt rulers, and called the people back to the worship of the Lord.
According to Second Kings 2:11, Elijah was taken into heaven in a whirlwind. Malachi's announcement of his future coming became an important foundation for Jewish expectations concerning the approach of divine redemption.
God promises to send Elijah the prophet before the great and awesome Day of the Lord. The announcement identifies Elijah as a preparatory figure whose mission precedes the decisive intervention of God. The following verse explains that his work will involve reconciliation and the restoration of covenant faithfulness.
The New Testament explicitly associates this promise with John the Baptist. John appeared before Jesus, called Israel to repentance, and prepared the people for the coming kingdom of God. Jesus identified John as the Elijah who was to come, while Luke explains that John ministered in the spirit and power of Elijah.
Matthew 11:14 records Jesus identifying John as the promised Elijah. Matthew 17:10-13 describes Jesus explaining that Elijah had already come, and the disciples understood Him to be speaking about John the Baptist. Luke 1:17 explicitly states that John would come in the spirit and power of Elijah.
John 1:21 records John denying that he was Elijah, a statement commonly understood as distinguishing his identity from a literal return of the ancient prophet.
Jewish tradition generally expects the future coming of Elijah as a herald of redemption. Elijah occupies an important place in Jewish religious expectation, including traditions associated with Passover. Judaism does not generally accept the Christian identification of John the Baptist as the fulfillment of this promise.
The Hebrew text names Elijah explicitly. The New Testament interprets the promise through John the Baptist's prophetic role rather than identifying him as the ancient Elijah returned in person. Some Christian traditions also anticipate a future fulfillment associated with the final Day of the Lord.