The sincere believer is afraid of six things
1. Loss of faith (Iman). Because in the following verse it is said: “[Who say], "Our Lord, let not our hearts deviate after You have guided us and grant us from Yourself mercy. Indeed, You are the Bestower. (Surat al-Imran 3:8)
2. The sincere believer is afraid that the malaikah will record things that will humiliate him on the Day of Resurrection. The verse commands: “That Day, the people will depart separated [into categories] to be shown [the result of] their deeds.” (Az-Zalzalah 99:6)
3. Fear that Shaytan will ruin his deeds. The verse says: [Iblees] said, "My Lord, because You have put me in error, I will surely make [disobedience] attractive to them on earth, and I will mislead them all.”(Surat al-Hijr 15:39)
4. Fear of death overtaking in a moment of carelessness or unpreparedness. The verse commands: “And worship your Lord until there comes to you the certainty (death).” (Surat al-Hijr 15:99) The hadith says the following: Jabir reported: The Messenger of Allah, peace and blessings be upon him, said, “Every servant will be resurrected upon the way that they died.” Source: Ṣaḥīḥ Muslim 2878
5. Fear of pride in earthly goods and carelessness for the afterlife. The verse commands: "And earthly life is only a deceptive pleasure." (Surat al-Imran 3:185)
6. Fear of insufficient mention of Allah (Zikr) due to excessive involvement in family affairs. The Holy Qur'an commands: “And know that your properties and your children are but a trial and that Allah has with Him a great reward.” (Surah Al-'Anfāl )