JhānavibhaṅgaSuttantabhājanīya

Abhidhammapiṭaka · Vibhaṅga · Vol. 35 · Section 683

[683] "Purity of mindfulness due to equanimity" (upekkhāsatipārisuddhiṃ): Therein, which is equanimity (upekkhā)? That which is equanimity, being equanimous, looking on with equanimity, neutrality of the mind (citta) — this is called equanimity. Therein, which is mindfulness (sati)? That which is mindfulness, recollection … right mindfulness — this is called mindfulness. This mindfulness, by means of this equanimity, is laid open, purified, and cleansed. Therefore it is said: "purity of mindfulness due to equanimity."

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.