Happiness is a milder expression of joy, or an expression of hope that something is moving towards joy.
The fact of the resurrection is like a science fiction story, except that it is real. We will all be raised to life at the last day of the existence of this earth... and maybe this whole universe. The resurrection for me is something that takes away a lot of fear of death. Jesus took the penalty for my mistakes in front of God. This makes my resurrection to be a joyful thing.
Oh sure. I fear the idea of having pain in this life, and in death. But I know that such pain will only last for a short time, even if it seems long, and that God is protecting me even in this life, because of what Jesus did for me (us). Then my time will be forever with God, Who wanted to be my Father, and Who became my Father rather than an enemy, because of what Jesus did for me (us) on the cross.
You can make my joy even greater, by showing me that you accept Jesus as your Savior. We will be in Heaven, together... in righteousness, for ever and ever.
Eternity is a long time. We need all the people we can get to be with us in Heaven, just so we can have joy in each other in eternity. I pity those who will not accept their Jesus-salvation. Eternity without God and without the joy of joyful contact even with other people will be terrible for them... as they are dissolved further and further toward nothingness for ever and ever.
