Make no mistake, my brothers, if anyone joins a schismatic he will not inherit God’s Kingdom. If anyone walks in the way of heresy, he is out of sympathy with the Passion. Be careful, then, to observe a single Eucharist. For there is one flesh of our Lord, Jesus Christ, and one cup of his blood that makes us one, and one altar, just as there is one bishop along with the presbytery and the deacons, my fellow slaves. In that way whatever you do is in line with God’s will.
--St. Ignatius of Antioch