Dhammapada · 25.4
Yo mukhasaññato bhikkhu, mantabhāṇī anuddhato;Atthaṃ dhammañca dīpeti, madhuraṃ tassa bhāsitaṃ.
Yo mukhasannato bhikkhu, mantabhani anuddhato; Attham dhammanca dipeti, madhuram tassa bhasitam.
The bhikkhu controlled in mouth, speaking wisely, not puffed up, who illuminates meaning and Dhamma — sweet is his speech.
— Dhammapada 25.4
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.