The arising of the enlightenment factor of mindfulness is the prerequisite for realizing the Dharma

The first of the seven factors of enlightenment is the enlightenment factor of mindfulness, which means that after studying a certain dharma, one understands this dharma, recognizes this dharma, and remembers this dharma. Once the dharma has entered the mind, the mind holds this dharma, and in daily life one can recollect and hold this dharma, think of this dharma, and contemplate this dharma, so that when encountering sense objects one can observe this dharma as it truly is—this is the prerequisite for realizing the dharma. If even one link or step in between is missing, both the enlightenment factor of mindfulness and the seven factors of enlightenment are incomplete, and one cannot realize the dharma. And once the dharma has entered the mind and can be recollected and held, one no longer needs to study this dharma every day with one's hands never leaving the book; otherwise, the enlightenment factor of mindfulness has not yet arisen. So at what stage of learning Buddhism and cultivating practice can one have the enlightenment factor of mindfulness?

What kind of person, after finishing the study of the dharma, no matter how they study, cannot let it enter the mind, cannot remember it, cannot recall it, and must rely on books to understand the dharma and to contemplate the dharma expounded in the books? Those who have not yet given rise to the enlightenment factor of mindfulness have no impression of or interest in the dharma—it is just like this; their power of mindfulness is very weak. Only after interest has been raised, and after one knows the importance of the dharma, can the mind now and then keep the dharma in mind.

For example, after finishing the study of the Hinayana dharma that the five aggregates are without self, one knows from reading books that the six sense objects—form, sound, smell, taste, touch, and dharmas—are all empty, false, and unreal. Yet after leaving the book and turning around to encounter the objects of the six sense fields, when seeing forms one is still very picky and very concerned, wanting the best and unwilling to suffer the slightest grievance; when hearing sounds, one is also very picky and very concerned; when smelling scents, one is also very picky and very attached to fragrance and stench; and the same goes for encountering touch and dharmas—very picky and attached—completely forgetting that just a moment ago one was reading the sentence that the six sense objects are false and unattainable. These phenomena show that this person has not let the dharma of the emptiness and falsity of the six sense objects enter the mind, lacks the capacity for recollection and retention, and cannot contemplate and observe; the enlightenment factor of mindfulness has not yet arisen. Then when will one realize the impermanence and non-self of the six sense objects? There is no date—perhaps in the year of the donkey, perhaps in the month of the horse.