He is the one about whom it was written [Mal. 3:1], 'Look, I [will] send my messenger on ahead of you. He will prepare the pathway in front of you.'

And if you are willing to accept [this truth], this person [i.e., John] fulfills [the prophecy of] the coming of Elijah. [See Mal. 4:5-6]

is quote from Mal. 3:1; verse

He is the one about whom it was written [Mal. 3:1], 'Look, I [will] send my messenger on ahead of you. He will prepare the pathway in front of you.'

Just as it is written [Mal. 1:2-3], "I [i.e., God] loved Jacob, but hated Esau."