For as the wind if it fall upon a slackened sail, would have no effect; so neither does the Spirit endure to continue in a slack soul; but there is need of much tension, of much vehemence, so that our mind may be on fire, and our conduct under all circumstances on the stretch, and braced up. For instance when we pray, we ought to do it with much intentness, stretching forth the soul toward Heaven, not with cords, but with great earnestness. Again when we do works of mercy, we have need of intentness, lest by any means, thought for our household, and care for children, and anxiety about wife, and fear of poverty entering in, should slacken our sail. For if we put it on the stretch on all sides by the hope of the things to come, it receives well the energy of the Spirit ; and none of those perishable and wretched things will fall upon it, yea, and if any of them should fall, it does it no harm, but is quickly thrown back by the tightness, and is shaken off and fails down.