John calls the saying in v. 1-6 a “proverb” (paroimian) rather than a parable. Generally parables seem to have one main point and should not be alegorized (i.e. making every part of the story represent something in the world). However the Parable of the Sower is one of several exceptions. However this saying seems to be something in between.
The Dictionary of Biblical Imagery, IVP, 1998 – says this: “Here we have more than a parable, though less than an allegory: it is an ‘image field’ full of rich figurative possibilities.”
So don’t get hung up on Jesus being both the door and the shepherd who goes through the door. And don’t look for a linear progression. Trying to outline this passage is difficult. It seems to us to be more like a weaving of threads, than anything like an outline.
The story before, with the blind man healed and accepted by Jesus, and rejected by the religious leaders, and the verses after this passage about some rejecting and some being intrigued, serve to illustrate points within. They are responding to the shepherds voice, or running from it.
Who is in and out of the flock? the flock within might be the people of Israel (but is that allegorizing too much?). Or perhaps it is a standing image of those who are “inside” in some way already. Those outside are the Gentiles. However in our day, if the image can traverse time in this way, those inside are those in the church, and those outside are those yet to hear. This could be a “missional” saying – let’s get outside of the walls.
How do we hear the Lord’s voice? It would seem that the Lord authenticates himself – we know his voice when we hear it.
We end with this quote from F. F. Bruce:
“What was to hold this enlarged flock together and supply the necessary protection from external enemies? Not enclosing walls but the person and power of the shepherd. The unity and safety of the people of Christ depend on their proximity to him. When they have forgotten this and tried to secure unity or safety by building walls round themselves, the results have not been encouraging. The walls have either been so comprehensive as to enclose a number of wolves along with the sheep with disastrous consequences for the sheep), or they have been so restrictive as to exclude more sheep than they enclose.” The Gospel of John, p. 228