Verily, verily, I say unto you, He that enters not by the door into the sheepfold, but climbs up some other way, the same is a thief and a robber.
All Commentaries on John 10:1 Go To John 10
Clement Of Alexandria
AD 215
But he that entereth in by the door is the shepherd of the sheep. To him the porter openeth. "Then the Lord says in explanation, "I am the door of the sheep."