Know that what is best for the slave in the state of health is for him to be fearful and hopeful, and that his fear and hope be equal. When he is ill, hope is purified. The bases of the Shari'a in the Book and the Sunna and elsewhere demonstrate that.
Allah Almighty says, "No one feels secure against Allah's devising except for those who are lost," (W7:98; H7:99)
and the Almighty says, "No one despairs of solace from Allah except for those who are unbelievers." (12:87)
The Almighty says, "On the Day when faces are whitened and some faces are blackened," (3:106)
and the Almighty says, "Your Lord is swift in retribution, and He is Ever-Forgiving, Most Merciful." (7:167)
The Almighty says, "The truly good will be in perfect Bliss,. The dissolute will be in the Blazing Fire," (82:13-14)
and the Almighty says, "As for him whose balance is heavy, he will have a most pleasant life. But as for him whose balance is light, his motherland is Hawiya." (W101:5-8; H101:6-9)
There are many ayats with this meaning and fear and hope are joined together in two consecutive ayats, several ayats or one ayat.
443. Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "If the believers knew the punishment which Allah has, none of them would have any hope of attaining His Garden. If the unbelievers knew the mercy which Allah has, none of them would despair of reaching His Garden." [Muslim]
444. Abu Sa'id al-Khudri reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "When a body is laid out and the men carry it on their shoulders, if it was righteous, it says, 'Take me forward,' and it was it not righteous, it says, 'Woe to me, where are you taking it?'' Everything except man hears its voice. If he were to hear it, he would faint." [al-Bukhari]
445. Ibn Mas'ud reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "The Garden is nearer to you than your own sandal strap and it is the same with the Fire." [al-Bukhari]
