תהלים, פרק צ״א, פסוק ה׳

Absolute trust in Divine providence grants a person complete protection at all hours, lifting away the worry of both hidden and visible dangers. The promise of living without fear is directly dependent on placing one's trust in God [רש״י]. Because a person rests under His shelter and defense, all fear naturally melts away [מצודת דוד].

The threats a person faces are split into two main times of day. Nighttime brings its own unique terrors, referring to disasters and events that strike in the dark [אבן עזרא, ביאור שטיינזלץ]. This dread often stems simply from the loneliness of walking or sitting alone in the shadows [רד״ק]. It also comes from the very real threat of enemies, assassins, and silent ambushes that use the cover of darkness to attack in secret [ביאור שטיינזלץ, מאירי].

In contrast, daytime holds the threat of sudden hazards that strike in broad daylight [אבן עזרא, רד״ק]. These dangers are likened to arrows, which are naturally shot during the day when a shooter can clearly see the target [ביאור שטיינזלץ]. The flight of these weapons represents their sudden and massive speed. Furthermore, the feathers attached to their ends give them the appearance of winged creatures flying through the air [רד״ק, מאירי]. Offering a completely different perspective, these daylight threats are not always seen as physical weapons. Instead, they can represent destructive demons that fly through the air with the speed of an arrow [רש״י].