註四十二章經 1.281

1.281

此佛誨誘學者，令知念念無常，在於呼吸，自然絕諸妄想，密密精進。若謂命在數日、或在食頃，則自寬其限，妄念隨生，涉於懈怠，安得成道也。

Here the Buddha instructs and guides students to make them realise that impermanence occurs thought-moment by thought-moment, hanging upon the breath. Then naturally all vain thoughts are severed, and they advance with continuous diligence. If one claims that life lasts a few days or the space of a meal, one slackens one's own deadline; vain thoughts arise accordingly, leading to indolence, and how could one ever accomplish the Way?