Surah 113. Al-Falaq, Ayah 3

I.e., the darkness of despair, or of approaching death. In all these four verses ({2-5}), the term "evil" (sharr) has not only an objective but also a subjective connotation - namely, fear of evil.

The darkness of the night, physical darkness, is a good type of physical dangers and difficulties. Many people are afraid of physical darkness, and all are afraid of physical injuries, accidents, and calamities. We should not fear, but having taken reasonable precautions, trust in Allah.