四分律行事鈔資持記 1.217

1.217

道打中，初文。出彼十六。佛在舍衛鹿母園中，夏竟受歲，令阿難打之。此是下，即阿難語。信鼓者，於事則告眾有期，在法則歸心無二。鼓謂擊動發聲，名通鐘磬。

In striking by monastics, first is the text. It comes from fascicle sixteen of that [vinaya]. When the Buddha was in Śrāvastī at the Mṛgāramātṛ-vihāra, having completed the rains retreat and receiving pravāraṇā, he ordered Ānanda to strike it. "This is..." downward is the speech of Ānanda. The "drum of faith" means that in phenomena, it announces to the assembly at the appointed time; in Dharma, their minds take refuge without duplicity. "Drum" means striking to emit sound, a term that applies generally to bells and chimes.