Uthmaan Ibn Affaan (ra) said:
"The believer has five types of Fear:

 

(1) The first is that Allaah may take his faith away from him.
(2) The second is that the recording Angels may write down something that may expose him on the Day of Resurrection.
(3) The third is that the Shaytan (Devil) may cause his deeds to become invalid.

(4) The fourth is that the Angel of Death may come to him without warning.
(5) The fifth is that this world may tempt him & distract him from the Hereafter."

 (Fara'id al-Kalam li'l-Khulafa al-Kiram, p.278)