In the account of John 10:1-10 Jesus is both the shepherd and the gate to the sheep pen. The latter part of the text focuses on Jesus being the gate.
A. Illustrate the Sheepfold and Gate: You can create a homemade sheepfold and toy sheep to illustrate the concept of Jesus being the gate of the sheep. (A miniature sand box would work too) Show the children how the shepherd would lead the sheep into the sheepfold at night for protection. Often the Shepherd would lie across the opening to the pen making himself literally a “gate”. Explain how Jesus is the gate, and that only through Him can we enter the Kingdom of God.
B. Blindfolded Obstacle Course: Set up an obstacle course and have the children take turns navigating it while blindfolded. At the end of the obstacle course you could have a sheep pen. Then, remove the blindfolds and guide the children through the course to illustrate how Jesus is the good shepherd who can lead his sheep. He is also the gate into the sheep pen. We must enter through this gate (Jesus) to enter the sheep pen.
C. Sheep Costume: Dress up a child in a sheep costume and have the other children pretend to be wolves or thieves. (Note: This can get a little chaotic!) Explain how the sheep only follow the shepherd's voice and that Jesus is our Good Shepherd who protects us from harm. Use a homemade shepherds staff to protect the sheep from the wolves. It could be a lot of fun! That will help them remember.
D. The Life / Maze Game: Create a maze on a large piece of paper and have the children take turns finding their way through it. Then, explain how life can often feel like a maze, but by following the Jesus (and his wisdom) we can find out way without getting lost.
Note: You may have a ready made object lesson if there is any “gate” on your church property. Alternately you can use any door in your church as a gate.