Only the Spirit of the Holy One can impart to the human spirit the knowledge of the holy. Yet as electric power flows only through a conductor, so the Spirit flows through Truth and must find some measure of Truth in the mind before It can illuminate the heart. Faith wakes at the voice of truth but responds to no other sound... Still, there must be humble penitence in the heart before Truth can produce faith.
The smile of the contemplative in the presence of the Beloved is merely a physical expression of the total joy one perceives as one communes with God. St. Bernard used to say, "The joy of being in love is in the very loving." In other words, joy is not to be sought for itself, but is a by-product of love, and the smile is but the physical, exterior expression of the inner joy-love.