7 “Verily, verily, I say unto you, Whoso hears my word, and believes in Him that sent me, has eternal life, and comes not into judgment, but is passed,” not is passing now, but is already passed, “from death into life.” And mark this, “Whoso hears my word, and”— He says not, believes me, but— “believes Him that sent me.” Let him hear the word of the Son, that he may believe the Father. Why hears Your word, and yet believes another? When we hear any one's word, is it not him that utters the word we believe? Is it not to him who speaks we lend our faith? What, then, did He mean, saying, “Whoso hears my word, and believes Him that sent me,” if it be not this, because “His word is in me”? And what is “hears my word,” but “hears me”? So, too, “believes Him that sent me,” because, believing Him, he believes His word; but again, believing His word, he believes me, because I am the Word of the Father. There is therefore peace in the Scriptures, and all things duly disposed, and in no way clashing. Cast away, then, contention from your heart; understand the harmony of the Scriptures. Do you think that the Truth should speak things contrary to itself?
Source: Tractates on the Gospel of John (New Advent)