The Lord wants us to make the effort to overcome our tendency to react badly to things or to hold back an intemperate word. Yet joy is not something we can order up. Joy is the fruit of love. There is no human love that can sustain a lasting joy. It often seems that human love is the source of more sorrow than joy. . . This is not the case in the Christian religion. A Christian who does not love God is a contradiction in terms. A Christian who does not radiate joy because of his love for God needs to take a closer look at his spiritual life. For the Christian, joy is something natural since it springs from the most important Christian virtue —love. Christian life and joy are essentially bound up together. There is also a relationship between sadness and lukewarmness, between sadness and egoism, between sadness and loneliness.
Joy can be increased or even recovered, if it is temporarily lost, with true prayer face to face with Jesus. This prayer ought to be personal and selfless. Frequent confession is the privileged source of holiness and peace. Authentic joy is based on this foundation: that we want to live for God and want to serve others because of God. Let us tell the Lord that we want nothing more than to serve him with joy. If we believe in this way we shall find that our inner peace, our joy, our good humor will attract many souls to God. Give witness to Christian joy. Show to those around you that this is our great secret. We are happy because we are children of God, because we deal with him, because we struggle to become better for him. And when we fail, we go right away to the Sacrament of joy where we recover our sense of fraternity with all men and women.
from In Conversation with God by Francis Fernandez p.154-155. Volume 5