Know, o brother, how vigilant a man would be, if he were to know that he has an enemy who, not content with destroying and suppressing him, is resolved to seize his wife, raper her in his presence and kill his children. He would be ever-vigilant, even while eating and drinking, sleeping or waking, to ward off his enemy.
As for the course to be followed, you must install the intellect in the center "upon the throne of his kingdom (Duet. 17.18). Then appoint the soul as his minister, the principal organs as close commanders and the secondary organs as servants in waiting, having each member carry out that which you deem appropriate. In this way, you will condemn your enemy and bind him "in fetters" and you will 'give judgment against him". (Jer 39.7, 5)
Therefore be sure to learn all the artifices with which he defense himself. "Neither shall your eye pity him", (Duet.12.9) for to be merciful towards evildoers is (to show them) inclemency, as the Sage has said, "For the mercy of the evil is cruel", (Prov. 12.10),
At prayer time, purify your niyyah (intention) and be thoroughly mindful of what you say. Beware not to harbor thoughts of anything else but the object of your devotion, lest the serpent's venom penetrate you at the moment of inattention and render your du`a (supplication) unacceptable and to no avail.
Consequently, as a preliminary to prayer, it is fitting to prepare oneself through the wuḍū (ablution) of one's hands and fee, restoring and arousing thereby the soul. Furthermore, always recite a preliminary Psalm so that you kavvanah (singular concentration) be engaged and avoid praying in ruined places lest you entertain foreign thoughts. ... pay no attention to people who content themselves at prayer time with concentrating on the first verse of the Shema' and the first paragraph [of the `Amīdah], for the Truth shall show the Path.