Just as a bubble may be seen,
just as a faint mirage,
so should the world be viewed
that the Death-king sees one not.
Explanation: Look at a bubble. How impermanent is it? Look at a mirage. What an illusion! If you look at the world in this way, even the king of death will not see you.
The Story of Many Monks (Verse 170)
While residing at the Jetavana Monastery, the Buddha spoke this verse, with reference to a group of monks.
On one occasion, a large number of monks, after taking a meditation topic from the Buddha, went into the forest to practice meditation. But they made very little progress: so they returned to the Buddha to ask for a more suitable subject of meditation. On their way to the Buddha, seeing a mirage they meditated on it. As soon as they entered the compound of the monastery, a storm broke out: as big drops of rain fell, bubbles were formed on the ground and soon disappeared. Seeing those bubbles, the monks stated, ‘This body of ours is perishable like the bubbles… and perceived the impermanent nature of the aggregates (khandhas). At the end of the discourse, the monks attained arahatship.
The Buddha saw them from his perfumed chamber and sent forth the radiance and appeared in their vision.