What did Jesus mean when He said 'I am the door of the sheep'?
Christ meant He is the only way, the sole door by which anyone may enter. That door is not hidden on a cliff, across a river, or beyond an ocean; it stands at ground level before every person. It is open to the whosoever will, and those who enter are chosen from before the world's foundation.
Les explains that Jesus clarified the parable because they did not understand. The statement "I am the door of the sheep" means He is the only way, and it is no different today, even though people try every other way but the way Christ has given. Les illustrates that the door to the sheepfold was not up on a sheer cliff, across a raging river, or on the other side of the ocean; it was right in front of them at ground level, where anybody could walk through. He connects this to the river of life lined with "whosoever will"; after one walks through and looks back, it reads "chosen from before the foundation of the world." Les also ties it to Romans 10: no one must ascend to bring Christ down or bring Him up from the deep, because He is right in front of every person. He then raises the question of those who have never heard the Gospel.
Then said Jesus unto them again, Verily, verily, I say unto you, I am the door of the sheep.