Ignatius to the Trallians 11

Shun ye therefore those vile offshoots that gender a deadly fruit, whereof if a man taste, forthwith he dieth. For these men are not the Father's planting: for if they had been, they would have been seen to be branches of the Cross, and their fruit imperishable -- the Cross whereby He through His passion inviteth us, being His members. Now it cannot be that a head should be found without members, seeing that God promiseth union, and this union is Himself.