Jesus knew that in twenty-four hours, He would be dead; nevertheless, He told His disciples,
“Therefore you now have sorrow; but I will see you again and your heart will rejoice, and your joy no one will take from you” (John 16:22).
Amazingly, He could speak of joy when He would see them again in a few days, even knowing the horrendous suffering just around the corner for Him.
The resurrection of Jesus Christ changed everything, and has changed the world forever, because of the joy of the disciples as they went out preaching on the resurrection of Jesus.
You can participate in the resurrection of Jesus by baptism (Romans 6:3, 4).
You can also have joy by doing what Jesus did, focusing on the future.