Mujahid narrated that Ibn 'Umar said:
The Messenger of Allah (s.a.w) grabbed me on part of my body and said: 'Be in the world like a stranger or a passerby, and count yourself among the inhabitants of the grave.' Ibn 'Umar said to me: When you wake up in the morning, then do not concern yourself with the evening. And when you reach the evening, then do not concern yourself with the morning. Take from your health before your illness, and from your life before your death, for indeed O slave of Allah! You do not know what your description shall be tomorrow. (sahih)