Many people in Jesus’ day owned sheep. It seems that a common practice was to put the flock in a pen at night, and let them out to graze during the day. So, it was really important to the sheep, when the shepherd arrived, and led the sheep out of the pen to the pasture. The pasture meant food, water, and life. The gate was the bridge to the pasture. That’s why Jesus said, “I am the gate.”
We all need “fuels” to live. We need physical fuels: food, water, and air. (Or you could use more resolution and say: Protein, iron, zinc. Vitamin C, vitamin D, etc.) We need spiritual fuels: love, purpose, beauty, etc.
Our primary spiritual fuel is a relationship with our Father. Everyone needs this sort of relationship to thrive. No just to exist, but to have what Jesus called “abundant life.”
And Jesus is the bridge to that life. Or, as the gate to the sheep pen, the way out to food and water for the sheep. Jesus is the gate that opens up, allowing people to escape the prison of sin, and experience life. Jesus is our means, our vehicle, for connecting with the Father.