John is saying, “You already have the answer if you would only remember that I have said all along that I am not the Christ but His forerunner.”

“You yourselves” and “I” are both emphatic.

John 1:20  He did not fail to confess, but confessed freely, “I am not the Christ.”

John 1:23  John replied in the words of Isaiah the prophet, “I am the voice of one calling in the desert, ‘Make straight the way for the Lord.’”

Mal 3:1  “See, I will send my messenger, who will prepare the way before me. Then suddenly the Lord you are seeking will come to his temple; the messenger of the covenant, whom you desire, will come,” says the LORD Almighty.

Mal 4:5  “See, I will send you the prophet Elijah before that great and dreadful day of the LORD comes.