The grounds of your justification are the perfect works of Jesus Christ. We're saved by works, but they're not our own.
R. C. SproulIt is important for us to make a distinction between the spiritual fruit of joy and the cultural concept of happiness. A Christian can have joy in his heart while there is still spiritual depression in his head. The joy that we have sustains us through these dark nights and is not quenched by spiritual depression. The joy of the Christian is one that survives all downturns in life.
R. C. Sproul