Malachi 4:5 Amplified Bible (AMP)
5 “Behold, I am going to send you Elijah the prophet before the coming of the great and terrible day of the Lord.

Malachi 3:1 Amplified Bible (AMP)
The Purifier
3 “Behold, I am going to send My [a]messenger, and he will prepare and clear the way before Me. And the Lord [the Messiah], whom you seek, will suddenly come to His temple; the [b]Messenger of the covenant, in whom you delight, behold, He is coming,” says the Lord of hosts.

Luke 3 Amplified Bible (AMP)
3 And he went into all the country around the Jordan, preaching a baptism of repentance for the forgiveness of sin; 4 as it is written and forever remains written in the book of the words of Isaiah the prophet,

“The voice of one shouting in the wilderness,
‘Prepare the way of the Lord,
[d]Make His paths straight.
5
‘Every ravine shall be filled up,
And every mountain and hill shall be leveled;
And the crooked [places] shall be made straight,
And the rough roads smooth;

and [e]all mankind shall see the salvation of God.’”

Isaiah 40:3-5 Amplified Bible (AMP)
3 A voice of one is calling out,“Clear the way for the Lord in the wilderness [remove the obstacles];Make straight and smooth in the desert a highway for our God.
4 “Every valley shall be raised,
And every mountain and hill be made low;
And let the rough ground become a plain,
And the rugged places a broad valley.
5
“And the glory and majesty and splendour of the Lord will be revealed,And all humanity shall see it together;
For the mouth of the Lord has spoken it.”
AMEN.