[10] Therein, what is internal feeling (vedanā ajjhattā)? Whatever feeling of these or those beings is internal, personal, one's own, individual, clung-to (upādinnā) — namely, pleasant feeling (sukhā vedanā), painful feeling (dukkhā vedanā), neither-painful-nor-pleasant feeling (adukkhamasukhā vedanā) — this is called internal feeling.
Therein, what is external feeling (vedanā bahiddhā)? Whatever feeling of these or those other beings, of other persons, is internal, personal, one's own, individual, clung-to — namely, pleasant feeling, painful feeling, neither-painful-nor-pleasant feeling — this is called external feeling.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.