أنغوتارا نيكايا 1:21
SUJATOIdaṁ kho, bhikkhave, atthavasaṁ paṭicca ‘maraṇadhammomhi, maraṇaṁ anatīto’ti abhiṇhaṁ paccavekkhitabbaṁ itthiyā vā purisena vā gahaṭṭhena vā pabbajitena vā.
This is the advantage of often reviewing this: ‘I am liable to die, I am not exempt from death’.