Dhammapada · 25.20
Attanā codayattānaṃ, paṭimāseattamattanā;So attagutto satimā, sukhaṃ bhikkhu vihāhisi.
Attana codayattanam, patimaseattamattana; So attagutto satima, sukham bhikkhu vihahisi.
Spur yourself yourself; examine yourself yourself. Self-guarded and mindful, O bhikkhu, you will live happily.
— Dhammapada 25.20
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.