Dhammapada · 23.7

Idaṃ pure cittamacāri cārikaṃ, yenicchakaṃ yatthakāmaṃ yathāsukhaṃ;Tadajjahaṃ niggahessāmi yoniso, hatthippabhinnaṃ viya aṅkusaggaho.

Idam pure cittamacari carikam, yenicchakam yatthakamam yathasukham; Tadajjaham niggahessami yoniso, hatthippabhinnam viya ankusaggaho.

Formerly this mind wandered as it wished, where it wished, as it pleased. Today I will restrain it thoroughly, as a goad-bearer restrains a rutting elephant.

— Dhammapada 23.7

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.