With every breath you take

‘The Buddha asked a Shramana [monastic], “How long is the human life span?” He replied, “A few days.” The Buddha said, “You have not yet understood the way.”

He asked another Shramana, “How long is the human life span?” The reply was, “The space of a meal.” The Buddha said, “You have not yet understood the way.”

He asked another Shramana, “How long is the human life span?” He replied, “The length of a single breath.” The Buddha said, “Excellent. You have understood the way.” 

This is the most immediate mindfulness of death, about the fragile and fleeting nature of life, and the importance of living moment to moment with Dharma practice as much as we can. Although we do not always have a morsel of food in our mouths, we are always breathing, and with each breath, life shortens; the next breath might not come.

Source : thedailyenlightenment.com