[761] Therein, what is loving-kindness (mettā)?
Here, at the time when a bhikkhu develops a form-sphere (rūpāvacara) jhāna that is functional (kiriya) — neither wholesome (kusala) nor unwholesome (akusala), nor a result of kamma (kammavipāka) — a pleasant abiding in the present life (diṭṭhadhammasukhavihāra): quite secluded from sensual pleasures … he enters and dwells in the first jhāna accompanied by loving-kindness. Whatever at that time is loving-kindness, the act of loving-kindness, the state of loving-kindness, loving-kindness as deliverance of mind (mettā cetovimutti) — this is called loving-kindness. The remaining phenomena (dhammā) are associated with loving-kindness.
Therein, what is loving-kindness? Here, at the time when a bhikkhu develops a form-sphere jhāna that is functional — neither wholesome nor unwholesome, nor a result of kamma — a pleasant abiding in the present life: with the stilling of thought-conception (vitakka) and discursive thought (vicāra) … the second jhāna … the third jhāna … the first jhāna … he enters and dwells in the fourth jhāna accompanied by loving-kindness. Whatever at that time is loving-kindness, the act of loving-kindness, the state of loving-kindness, loving-kindness as deliverance of mind — this is called loving-kindness. The remaining phenomena are associated with loving-kindness.
Therein, what is compassion (karuṇā)? …
Therein, what is altruistic joy (muditā)? …
Therein, what is equanimity (upekkhā)? Here, at the time when a bhikkhu develops a form-sphere jhāna that is functional — neither wholesome nor unwholesome, nor a result of kamma — a pleasant abiding in the present life: with the abandoning of pleasure (sukha) and … he enters and dwells in the fourth jhāna accompanied by equanimity. Whatever at that time is equanimity, the act of equanimity, the state of equanimity, equanimity as deliverance of mind — this is called equanimity. The remaining phenomena are associated with equanimity.
The Analysis According to the Abhidhamma (Abhidhammabhājanīya).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.