Jn 15:9-11
[Jesus said to his disciples,] 9“As the Father loves me, so I also love you. Remain in my love. 10If you keep my commandments, you will remain in my love, just as I have kept my Father’s commandments and remain in his love. 11“I have told you this so that my joy might be in you and your joy might be complete.”
THAT MY JOY MIGHT BE IN YOU: Joy (Greek chara) is a feeling that makes the “heart dance,” and fills the person with happiness. One’s joy may be found in one’s beloved, in the gift of a child, in the fruits of one’s labors, in participation at festive occasions, in the contemplation of God’s handiworks.
Jesus’ joy comes with his intimacy with the Father. After his encounter with the Samaritan woman, he tells his disciples who have brought him something to eat that his food (or his joy) is to do the will of the one who sent him and to finish his work (Jn 4:34). His joy lies in knowing that he always does the will of the Father.
Even at the Last Supper, just before he undergoes his passion, Jesus can speak of his joy. This is because Jesus focuses not on the tragedy of the cross but on the glorification of the Father to which the paschal mystery leads.
The joy of Jesus is what he shares with his disciples. In the world, they will have trouble, precisely because they are followers of Jesus. But with his death and resurrection, Jesus overcomes the world (Jn 16:33), and this is the source of true joy, a joy that no one can take away from them. Moreover, with his resurrection, Jesus will give them the Holy Spirit who will make them joyful and courageous, even amid trials.