Most Simply:

Jesus.  Our hope and joy are bound up in who He is and what He's done.

The Gospel ("Good News") of Jesus:

Though all have sinned against the creator God 
- and all deserve punishment for their sin, 
God loved us enough to become one of us, 
living the life we ought to have lived, 
and dying the death we deserved to die.  
He rose from the dead on the third day, 
conquering death in our place.  

We gladly accept the good news ("Gospel") that what happened to Jesus counts for those who believe and repent (turning away from rebellion to Him).  
Those who believe are forgiven, given eternal life, adopted as children of God, and are transformed from the inside out to be more and more like Jesus.  
By faith in Jesus we enjoy what Jesus deserves since Jesus suffered what we deserved on a cross.

For more detail about our convictions that stem from the Gospel, click the links below