What does John 17:10 mean?

Now they have known that all things whatever you have given me are from you,

for the words which you have given me I have given to them, and they received them, and knew for sure that I came from you, and they have believed that you sent me.

I pray for them. I don’t pray for the world, but for those whom you have given me, for they are yours.

I am no more in the world, but these are in the world, and I am coming to you. Holy Father, keep them through your name which you have given me, that they may be one, even as we are.

While I was with them in the world, I kept them in your name. Those whom you have given me I have kept. None of them is lost, except the son of destruction, that the Scripture might be fulfilled.

But now I come to you, and I say these things in the world, that they may have my joy made full in themselves.