Once you and I truly experience the joy of the Lord, no one can rob us of that joy!
That does not mean that we will never experience disappointment, sorrow or grief; but it does mean that deeps down underneath it all is the joy that comes as a gift from God, the fruit of the Spirit. And that is the kind of joy that no one can take away.
Underneath the tears, the heartache, lies the calm, sweet peace that God gives to those who walk in faith and obedience. And that is a part of the joy that He promises.
Jesus' promise to see His disciples again, of course, refers to after the resurrection. "You will be so firmly persuaded that I have risen," He says to them, "and that I am the Messiah, that neither the threats nor the persecutions of men will ever be able to shake your faith, or produce doubt or unbelief and thus take away your joy."
Jesus' prediction, as we know, was remarkably fulfilled, for after He revealed Himself to them following the resurrection, not one of the apostles ever doubted for a moment that He has risen from the dead. No trial or persecution was able to shake their faith - so that their joy remained.
You and I have certainties of faith that are unshakable, and thus they produce joy - joy that will remain forever and ever.
Jesus knew they were dying to ask him what he meant, so he said, "Are you trying to figure out among yourselves what I meant when I said, 'In a day or so you're not going to see me, but then in another day or so you will see me'? Then fix this firmly in your minds: You're going to be in deep mourning while the godless world throws a party. You'll be sad, very sad, but your sadness will develop into gladness."
"When a woman gives birth, she has a hard time, there's no getting around it. But when the baby is born, there is joy in the birth. This new life in the world wipes out memory of the pain. The sadness you have right now is similar to that pain, but the coming joy is also similar. When I see you again, you'll be full of joy, and it will be a joy no one can rob from you. You'll no longer be so full of questions."
"This is what I want you to do: Ask the Father for whatever is in keeping with the things I've revealed to you. Ask in my name, according to my will, and he'll most certainly give it to you. Your joy will be a river overflowing its banks!" (John 16:19-24, MSG)