SaṁmappadhānavibhaṅgasuttantabhājanīyaAbhidhaṁbhājanīya

Abhidhammapiṭaka · Vibhaṅga · Vol. 35 · Section 499

[499] "He exerts the mind (citta)": therein, what is the mind? That which is mind, mentality (mano), mentation (mānasa) … the corresponding mind-consciousness element (tajjā manoviññāṇadhātu) — this is called the mind. He exerts, thoroughly exerts, supports, and firmly supports this mind. Therefore it is said: "he exerts the mind."

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 3 other places