Narrated from Sayyiduna Khabbab (may Allah be pleased with him):
He had seven scars on his body and used to say: My companions departed from this world before me, and the world could not diminish their reward (because they were not engrossed in the world), and now we have so much wealth that we find no place to keep it except in the earth. And if the Noble Prophet (peace and blessings of Allah be upon him) had not forbidden us from asking for death, I would surely have prayed for death.

Sayyiduna Abu Hurairah (may Allah be pleased with him) says: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: "No one can enter Paradise because of his (good) deeds." The Companions (may Allah be pleased with them) asked: "Not even you, O Messenger of Allah! (Can you not enter Paradise because of your good deeds?)" He (peace and blessings of Allah be upon him) replied: "No, not even I (can enter Paradise because of my deeds), unless Allah covers me with His (cloak of) mercy. So you should adopt moderation and seek closeness to Allah, and no one should wish for death, because if a person is righteous, he will increase in his goodness (by living), and if he is a sinner, perhaps he may repent."

Umm al-Mu’minin Aisha (may Allah be pleased with her) says that whenever the Messenger of Allah (peace and blessings be upon him) would visit a sick person or a sick person was brought to him (the narrator is unsure), he (peace and blessings be upon him) would recite this supplication:“Lord of the worlds! Remove the illness of the people and grant healing. There is no healer except You. You are the Healer. Grant such a healing that no illness remains.”