The Long Āgama Sūtra 9.4

9.4

爾時，世尊以十五日月滿時，於露地坐，諸比丘僧前後圍繞。世尊於夜多說法已，告舍利弗言：「今者四方諸比丘集，皆共精勤，捐除睡眠，吾患背痛，欲暫止息，汝今可為諸比丘說法。」

It was the fifteenth-day full moon when the Bhagavān sat in an open area with the assembly of monks both in front and behind him. After he had given them many discourses on the Dharma that evening, the Bhagavān addressed Śāriputra, “The monks have gathered today from the four directions to diligently apply themselves together. They aren’t sleepy yet, but I’m suffering from back pain. I’d like to take a break for a while. Perhaps you can explain the Dharma for the monks now?”