An-Nawawi’s Hadith No.40
On the authority of Abdullah bin Omar (Radhiallaho anha), who said:
The Messenger of Allah (Sallallaahu 'alaihi wasallam) took me by the shoulder and said:
"Be in the world as though you were a stranger or a wayfarer."
Ibn Omar (Radhiallaho anha), The son of Omar used to say:
"At evening do not expect [to live till] morning, and at morning do not expect [to live till] evening. Take from your health for your illness and from your life for your death."
Related by al-Bukhari