The identification of the word "night" as the name of an angel originates with an interpretation of Genesis 14:15 found in the Babylonian Talmud Sanhedrin 96a.
As in Niddah 16b, God decrees everything about the unborn child's fate except whether it will be righteous or wicked, since this is a choice the individual has to make for themself.
[6] Folklorist Howard Schwartz has claimed that unlike most angels, Lailah exhibits "distinctly feminine characteristics".
[7][8] Schwartz suggests that Lailah is the polar opposite of Lilith, who wastes seed, is not maternal, and is bent on destruction, not creation.
[7] The word "night" appears hundreds of times in the Hebrew Bible and continues to be the subject of rabbinic discussion.