ט֚וֹב אֲשֶׁ֣ר תֶּאֱחֹ֣ז בָּזֶ֔ה וְגַם־מִזֶּ֖ה אַל־תַּנַּ֣ח אֶת־יָדֶ֑ךָ כִּֽי־יְרֵ֥א אֱלֹהִ֖ים יֵצֵ֥א אֶת־כֻּלָּֽם׃
Dobrze jest, abyś się tego trzymał, a i od drugiego nie puszczał ręki twojej; bo kto Boga się obawia, unika tego wszystkiego.
Zohar
"...As light is superior to darkness." (Kohelet 2:13) The benefit of light only comes from darkness. What is the fixing (tikkun) of white? Black. If it were not for black one would never know white, because blackness causes whiteness to disappear become more precious. R' Yitzchak says, this is like the bitter and the sweet - one does not know what is sweet until they have tasted bitterness. What therefore makes something sweet, wouldn't we say the bitter? This is what is written "...The one no less than the other was God’s doing..." (Kohelet 7:14)