法苑珠林 42.24

42.24

如大遺教經云。比丘欲食時。當為檀越燒香三唄。讚揚布施可食美食。又從上座教言。道士各自出澡手漱口已還各就座而坐。各說一偈。以隨次起。不得踰越。

As the Da yijiao jing states: "When monks are about to eat, they should burn incense for the dānapati and chant three pāṭhas, praising dāna before they may eat fine food. Furthermore, following the instructions of the senior monk, the practitioners each go out to wash their hands and rinse their mouths, then each returns to take their seat. Each recites a verse and then rises in proper sequence, without skipping over others."