On the authority of Abdullah ibn Umar (ra), who said:

The Messenger of Allah (saw) took me by the shoulder and said,

“Be in this world as though you were a stranger or a wayfarer.”

And Ibn Umar (ra) used to say,

“In the evening do not expect [to live until] the morning, and in the morning do not expect [to live until] the evening. Take [advantage of] your health before times of sickness, and [take advantage of] your life before your death.”

[Bukhari]