Sometimes people find themselves brightly illuminated and refreshed by God’s grace for a while, but then this grace may be taken away, and they can fall into depression and start grumbling and even give up dispiritedly instead of energetically renewing their prayers to call down again that assurance of salvation. Such behavior is like an ungrateful beggar taking alms at the palace door and then walking off indignantly because he was not invited in to dine with the king himself.
–Saint John of Karpathos (Seventh Century)