[758] Therein, what is altruistic joy (muditā)?
Here, on whatever occasion a bhikkhu develops the path (magga) for rebirth in the form sphere (rūpūpapatti), quite secluded from sensual pleasures (kāma) … enters and dwells in the first jhāna accompanied by altruistic joy (muditāsahagata) — on that occasion there is contact (phassa) … there is non-distraction (avikkhepa). These phenomena (dhammā) are wholesome (kusala).
Because that same form-sphere (rūpāvacara) wholesome kamma has been done and accumulated, as its result (vipāka), quite secluded from sensual pleasures … he enters and dwells in the first jhāna accompanied by altruistic joy. That which on that occasion is altruistic joy, the act of rejoicing (muditāyanā), the state of rejoicing (muditāyitatta), altruistic joy as deliverance of mind (muditā cetovimutti) — this is called altruistic joy. The remaining phenomena are associated (sampayutta) with altruistic joy.
Therein, what is altruistic joy?
Here, on whatever occasion a bhikkhu develops the path for rebirth in the form sphere, with the stilling (vūpasama) of thought-conception (vitakka) and discursive thought (vicāra) … enters and dwells in the second jhāna accompanied by altruistic joy — on that occasion there is contact … there is non-distraction. These phenomena are wholesome.
Because that same form-sphere wholesome kamma has been done and accumulated, as its result, with the stilling of thought-conception and discursive thought … the second jhāna … the third jhāna … the first jhāna … he enters and dwells in the fourth jhāna accompanied by altruistic joy. That which on that occasion is altruistic joy, the act of rejoicing, the state of rejoicing, altruistic joy as deliverance of mind — this is called altruistic joy. The remaining phenomena are associated with altruistic joy.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.