The expression "habitual reminders" is a part of the vocabulary of spiritual theology and means the practice of calling God habitually to mind. The phylacteries, small receptacles bound to the forehead and arm by Jews at prayer, remind them of God, as do religious festivals such as Passover, Temple worship, and grace before meals. In the gospels, Jesus commanded that the Last Supper be observed as a reminder of his death until he returned. The basic psychological fact here is that just as we are taught to brush our teeth regularly after meals until it becomes second nature, so too habitual reminders accustom us to live more and more in God's presence.

Diogenes Allen, Spiritual Theology