Saṃyutta Nikāya - The Connected Discourses
Connected Discourses with Radha: SN23:16 Of Painful Nature
1 Sāvatthinidānaṃ. Ekamantaṃ nisinno kho āyasmā rādho bhagavantaṃ etadavoca: "‘dukkhadhammo, dukkhadhammo’ti, bhante, vuccati. Katamo nu kho, bhante, dukkhadhammo"ti? "Rūpaṃ kho, rādha, dukkhadhammo, vedanā dukkhadhammo, saññā dukkhadhammo, sankhārā dukkhadhammo, viññāṇaṃ dukkhadhammo. Evaṃ passaṃ … pe … nāparaṃ itthattāyāti pajānātī"ti.
Chaṭṭhaṃ.