Is that why Christ almost always preceeded his teaching with “it is written...?”
Was He referring to the New Testament, which did not yet exist? Or is the Old Testament to be our guide?
Notice that He doesn't command us to settle intra-Christian disputes via Scripture.
"If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, treat him as you would a pagan or a tax collector."