“Mendicants, there are five kinds of hard-heartedness. What five? Firstly, a mendicant has doubts about the Teacher. They’re uncertain, undecided, and lacking confidence. This being so, their mind doesn’t incline toward keenness, commitment, persistence, and striving. This is the first kind of hard-heartedness.

Furthermore, a mendicant has doubts about the teaching … the Saṅgha … the training … A mendicant is angry and upset with their spiritual companions, resentful and closed off. This being so, their mind doesn’t incline toward keenness, commitment, persistence, and striving. This is the fifth kind of hard-heartedness.

To give up these five kinds of hard-heartedness you should develop the four kinds of mindfulness meditation. …”

Numbered Discourses 9.72 7. Mindfulness Meditation Shackles of the Heart

“Mendicants, there are these five shackles of the heart. What five? Firstly, a mendicant isn’t free of greed, desire, fondness, thirst, passion, and craving for sensual pleasures. This being so, their mind doesn’t incline toward keenness, commitment, persistence, and striving. This is the first shackle of the heart.