Iti 86
Itivuttaka: The Group of Threes
translated from the Pali by
Thanissaro Bhikkhu
This was said by the Blessed One, said by the Arahant, so I have heard: "With reference to a monk who practices the Dhamma in accordance with the Dhamma, it is this way of according with the Dhamma that he should be described as practicing the Dhamma in accordance with the Dhamma. When speaking, he speaks Dhamma and not non-Dhamma. When thinking, he thinks about Dhamma and not about non-Dhamma. Avoiding both these things, he stays equanimous, mindful, alert."
Dhamma his dwelling, Dhamma his delight, a monk pondering Dhamma, calling Dhamma to mind, doesn't fall away from true Dhamma.
Whether walking, standing, sitting, or lying down his mind inwardly restrained he arrives right at peace.