Charles Ellicott Commentary John 1:22

"They said therefore unto him, Who art thou? that we may give an answer to them that sent us. What sayest thou of thyself?" — John 1:22 (ASV)

That we may give an answer.—He has given the “No” to all the ideas they had formed about him. There is nothing left to them but to draw the definite statement from himself, or to return to their senders empty-handed.