Dutiyagelaññasutta

Suttapiṭaka · Saṁyuttanikāya · Saḷāyatanavaggasaṁyutta · Vol. 18 · Section 382

[382] On one occasion the Blessed One was dwelling at Vesālī, in the Great Wood, in the Hall with the Peaked Roof. Then, in the evening, the Blessed One emerged from seclusion and approached the sick ward; having approached, he sat down on the seat prepared for him. Having sat down, the Blessed One addressed the bhikkhus: "Bhikkhus, a bhikkhu should await his time mindful (sato) and clearly comprehending (sampajāno). This is our instruction to you."

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 19 · Section 682 — Satisutta