The messenger of God is often sad, but his sadness does not come from causes relating to himself. He longs that a soul become illumined, but the soul prefers darkness; he yearns to change the ignorance of the people into knowledge, their error into guidance, their insincerity into truth, their faithlessness into firmness; but people prefer their own shadows and he who manifests God becomes sad over the negligence of these sleeping ones. Are they not of the heedless? When I am sad, I always pray.
(‘Abdu’l-Bahá, Divine Philosophy, p. 73-74)