He's still using the metaphor of sheep, so we imagine a flock of sheep pushing against the fence, needing the comforts offered inside and needing protection from the dangers out there where they now are.
Until they can find the gate that will let them in, they are stuck there outside.
Jesus says, "I am the gate." I am the way that the sheep can escape dangers and get into the pasture.
Let's not restrict Jesus' promise to afterlife only. He's telling us sheep that there is a way out of our troubles and a way into what we need now.
Gail O'Day and Susan Hylen, in their commentary on John:
The image of sheep finding pasture echoes the promises made in Ezekiel: "I will feed them with good pasture; there they shall lie down in good grazing land, and they shall feed on rich pasture on the mountains of Israel: (Ezek 34:14; also see Psalm 23:2).