Our assurance, our glory, and the sole anchor of our salvation are that Christ the Son of God is ours, and we in turn are in him sons of God and heirs of the Kingdom of Heaven, called to the hope of eternal blessedness by God's grace, not by our worth.
John CalvinRejoicing refers to moderation of spirit when the mind keeps itself in calmness under adversity and does not give indulgence to grief. Constant praying is the way of 'rejoicing perpetually', for by this means we ask from God alleviation in connection with all our distresses.
John Calvin