Dhammapada · 10.5

Māvoca pharusaṃ kañci, vuttā paṭivadeyyu taṃ;Dukkhā hi sārambhakathā, paṭidaṇḍā phuseyyu taṃ.

Mavoca pharusam kanci, vutta pativadeyyu tam; Dukkha hi sarambhakatha, patidanda phuseyyu tam.

Speak harshly to no one; those spoken to may answer back. Painful is angry talk; blows in return may touch you.

— Dhammapada 10.5

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.