Dhammapada · 12.9
Attanā hi kataṃ pāpaṃ, attanā saṃkilissati;Attanā akataṃ pāpaṃ, attanāva visujjhati;Suddhī asuddhi paccattaṃ, nāñño aññaṃ visodhaye.
Attana hi katam papam, attana samkilissati; Attana akatam papam, attanava visujjhati; Suddhi asuddhi paccattam, nanno annam visodhaye.
Evil done by oneself defiles oneself; evil not done by oneself purifies oneself. Purity and impurity are personal — no one can purify another.
— Dhammapada 12.9
Source: Pali text from the Khuddaka Nikāya of the Pali Canon (oldest extant Buddhist scripture, compiled c. 3rd century BCE). Public-domain English readings drawn from F. Max Müller's translation in Sacred Books of the East, Vol X (1881) and the Buddhist Publication Society's freely-licensed Acharya Buddharakkhita rendering.