17 O how gracious is the Lord! O how measureless are His mercies! Happy the race of mortals when God confesses it! Woe to the soul which He denies! Fire is stored up for its punishment. Be of good cheer, my son, in hope; sow good [seed] and faint not. The husbandman sows in hope, and the merchant journeys in hope, you also love good [seed]; in the hope look for the reward. Do nothing at all without the beginning of prayer. With the sign of the living cross, seal all your doings, my son. Go not forth from the door of your house till you have signed the cross. Whether in eating or in drinking, whether in sleeping or in waking, whether in your house or on the road, or again in the season of leisure, neglect not this sign; for there is no guardian like it. It shall be unto you as a wall, in the forefront of all your doings. And teach this to your children, that heedfully they be conformed to it.
Source: On Admonition and Repentance (New Advent)