Cetokhilasutta
“Pañcime, bhikkhave, cetokhilā. Katame pañca? Idha, bhikkhave, bhikkhu satthari kaṅkhati vicikicchati nādhimuccati na sampasīdati. Yo so, bhikkhave, bhikkhu satthari kaṅkhati vicikicchati nādhimuccati na sampasīdati, tassa cittaṁ na namati ātappāya anuyogāya sātaccāya padhānāya. Yassa cittaṁ na namati ātappāya anuyogāya sātaccāya padhānāya, ayaṁ paṭhamo cetokhilo.
Hard-heartedness
“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.