en_tn_condensed/mat/11/10.md

This is he of whom it was written

"He is the one about whom a prophet wrote long ago" or "This is what a prophet wrote long ago about John the Baptist"

I am sending my messenger

The pronouns "I" and "my" refer to God. The prophet was quoting what God said.

before your face

Here "your" is singular, because God was speaking to the Messiah in the quotation. Also, "face" refers to the whole person. Alternate translation: "in front of you" or "to go ahead of you"

prepare your way before you

This means the messenger will prepare the people to receive the Messiah's message.