If you pour oil and vinegar into the same vessel, you would call them not friends but opponents.
AeschylusThe great and amorous sky curved over the earth, and lay upon her as a pure lover. The rain, the humid flux descending from heaven for both man and animal, for both thick and strong, germinated the wheat, swelled the furrows with fecund mud and brought forth the buds in the orchards. And it is I who empowered these moist espousals, I the great Aphrodite.
Aeschylus