What is the meaning of "Tashes Choshech"?
Rashi: Every day You darken the sun, and it is night.
What is the benefit of night?
Radak: There is benefit (a) for predatory animals (refer to 104:20:3:1), (b) for man, and the big 1 animals with him, to rest from their toil, and (c) darkness and light cause existence and loss.
Eruvin 65a #1: Night was made for sleeping. (Me'iri - one should sleep at night so he can learn during the day without sleeping.)
Eruvin 65a #2: Moonlight is to enable people to stay up at night and learn Oral Torah.
I.e. animals used for work, e.g. cattle and donkeys. (PF)
Do forest Chayos go only at night?
Bava Metzi'a 83b: "Lailah" refers to this world, which resembles night 1 . "Kol Chayso Ya'ar" refers to the wicked, who are like beasts of the forest.
Radak: Yes. Lions and other predatory animals go out only at night. You did not let them leave their borders during the day, lest they damage people. You put fear of people on them - "u'Mora'achem v'Chitechem Yihyeh Al Kol Chayas ha'Aretz" (Bereishis 9:2). Due to this, they go out to seek prey only at night. "Tirmos" is going, like "uv'Chol ha'Chayah ha'Romeses Al ha'Aretz" (ibid., 1;28). The Vov at the end of "Chayso" is extra, like the Vov in "Beno Be'or" (Bamidbar 24:3).
Mesilas Yesharim (Perek 3): Darkness of night causes two kinds of mistakes. It covers the eye, so he does not see what is in front of him at all. Or, it makes him err, so a pillar appears like a person. So physicality of this world, it is darkness of need to the intellect. It does not let one see stumbling blocks in the ways of the world, and it distorts vision, so people see evil as if it is truly good, and good as if it is evil.
