These words introduce a quotation from the prophet Isaiah. They can be stated in active form, and the missing words can be supplied. Alternate translation: "This happened as Isaiah the prophet had written in the book that contains his words:" or "John fulfilled the message that the prophet Isaiah had written in his book:" (See: [[rc://en/ta/man/jit/figs-activepassive]] and [[rc://en/ta/man/jit/figs-explicit]])
This can be expressed as a sentence. Alternate translation: "The voice of one calling out in the wilderness is heard" or "They hear the sound of someone calling out in the wilderness"
"Get the road ready for the Lord." Doing this represents preparing to hear the Lord's message when he comes. Alternate translation: "Prepare yourselves for the Lord to come" or "Be ready for the Lord when he comes" (See: [[rc://en/ta/man/jit/figs-metaphor]])