Jesus is the unifier between the Western and Eastern churches.
And the word of God, the Bible.
Also, Paul’s letters to the western and eastern churches (e.g. look at the differences between the letter to the Romans versus the letter to the Colossians) are also the unifier.
Oh, you are so boringly predictable. He said it was a path, meaning one among many options. In fact, the Bible is something the Catholics and Orthodox have in common, since neither followed the anti-Christ expunging of several parts of Scripture committed by the participants at Jamnia, and adopted by the “Reformed” Christians.