The Long Āgama Sūtra 2.72

2.72

爾時，世尊遙見五百隷車，車馬數萬，填道而來，告諸比丘：「汝等欲知忉利諸天遊戲園觀，威儀容飾，與此無異。汝等比丘！當自攝心，具諸威儀。云何比丘自攝其心？於是比丘內身身觀，精勤不懈，憶念不忘，捨世貪憂；外身身觀，精勤不懈，憶念不忘，捨世貪憂；內外身觀，精勤不懈，捨世貪憂。受、意、法觀，亦復如是。云何比丘具諸威儀？於是比丘可行知行，可止知止，左右顧視，屈伸俯仰，攝持衣鉢，食飲湯藥，不失宜則，善設方便，除去蔭蓋，行住坐臥，覺寤語默，攝心不亂，是謂比丘具諸威儀。」

The Bhagavān saw those 500 Licchavi chariots from afar, their horses were so numerous, filling the road as they approached. He told the monks, “If you want to know how dignified-looking and decorated the Trāyastriṃśa gods are when they entertain themselves in their scenic parks, it’s no different than this.

“You monks, you should collect your thoughts and behave in a dignified manner. How does a monk collect his thoughts? Here, a monk observes body internally to be body. Diligent and unflagging, he’s mindful and doesn’t forget it, setting aside worldly greed and sorrow. He observes body externally to be body. Diligent and unflagging, he’s mindful and doesn’t forget it, setting aside worldly greed and sorrow. He observes body internally and externally to be body. Diligent and unflagging, he’s mindful and doesn’t forget it, setting aside worldly greed and sorrow. He also observes feelings, mind, and principles in the same way.

“How does a monk behave in a dignified manner? Here, a monk knows to walk when he should walk and to stop when he should stop. He looks left and right before bending and stretching, looking down and up, or gathering his robes and bowl. When he eats, drinks, and takes medicine, he doesn’t forget what’s appropriate. He skillfully prepares when relieving himself, taking away screens, while walking, standing, sitting, and lying down, and while awake, asleep, speaking, and being quiet. He collects his thoughts and isn’t disturbed. This is a monk who behaves in a dignified manner.”