Imam Ghazali (ra) says: “Fear rips away desires and muddens luxuries so that cherished sins become reprehensible, just as a honey lover is repelled by it when he learns that it has poison in it. This is how fear burns desires; disciplines the organs; subordinates the heart and gives it tranquility. It also enables the heart to rid itself of pride, hatred, and envy; and it leaves it absorbed in it (fear). Hence, the heart becomes preoccupied with its own worries and looks towards its best interest in the long run. It is then engaged in only matters like meditation, self-analysis and struggle. It cherishes its time and moments.”
Abdullah ibn Mubarak (ra) said about fear: When night befalls, they endure it and see it through bowing in ruku. Fear has released their sleep, so they stand and acquire security in vigilance.
Hasan ibn Hani (ra) composed the following:
Fear Allah and hope for every good thing from Him;
Don’t follow your adamant self, lest you regret it;
Remain in between hope and fear and you will
rejoice with the Pardon of Allah if you submit.