Jesus clearly indicates in this chapter that the Pharisees were not only blind, but also false shepherds, described in verses 5 and 8 as strangers and thieves.
In verse 10, we read the third "I am" pronounced by Jesus as "The door of the sheep", this image contrasts the protection that Jesus gives to the sheep in the fold with the usurpers, the false prophets of the OT and the false messiahs of the most recent times.
Entering the fold through Jesus is a saving action and provides the sheep with abundant life and provisions.
The phrase "will come and go" does not mean that you can hesitate between being in Christ at one time and outside of Christ the next, the scene offers a picture of safety and salvation in Christ as the door of the fold for the sheep to go and come daily.
The fourth "I am" in verse 14 of Jesus declares that He is the good shepherd, whose genuine concern for his sheep contrasts with the behavior of the wage earner, who is only interested in his own benefit.