註四十二章經 1.23

1.23

凡經首標佛言者，皆是弟子阿難等結集之時，敘佛平生所說，故云佛言。

Whenever a sūtra begins with "The Buddha said," this was spoken when disciples such as Ānanda compiled the teachings, narrating what the Buddha spoke during his lifetime; hence it says "The Buddha said."