Берешит 4:8 Каббала: Zohar

וַיֹּ֥אמֶר קַ֖יִן אֶל־הֶ֣בֶל אָחִ֑יו וַֽיְהִי֙ בִּהְיוֹתָ֣ם בַּשָּׂדֶ֔ה וַיָּ֥קָם קַ֛יִן אֶל־הֶ֥בֶל אָחִ֖יו וַיַּהַרְגֵֽהוּ׃

Каин заговорил со своим братом Ѓевелем. И когда они были в поле, Каин набросился на своего брата Ѓевеля и убил его.

Zohar

Mark this! As Job kept evil separate from good and failed to fuse them, he was judged accordingly: first he experienced good, then what was evil, then again good. For man should be cognizant of both good and evil, and turn evil itself into good. This is a deep tenet of faith.