[600] For whomever, wherever, the equanimity faculty (upekkhindriya) arises, does the mind faculty (manindriya) arise for that one there?
Yes.
Or rather, for whomever, wherever, the mind faculty arises, does the equanimity faculty arise for that one there?
For those possessing mind (sacittaka) who are being reborn without equanimity (upekkhā), and, in the course of existence (pavatta), at the moment of arising (uppādakkhaṇa) of a mind (citta) dissociated from equanimity — for them, there, the mind faculty arises, but the equanimity faculty does not arise for them there. For those who are being reborn with equanimity, and, in the course of existence, at the moment of arising of a mind associated with equanimity — for them, there, the mind faculty arises and the equanimity faculty arises.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.