“They also worshipped the sun and the moon and two gods to whom they assigned a higher value than to other gods. One they called Bialbug – that is the white god, believing him to be a good god, the other Zernebug – that is the black god, believing him to be a god who did harm. Therefore, they honored Bialbug so that he should do them good, and Zernebug so that he should not harm them … “. This passage contains the strongest assertion yet about the Slavs’ dualism of worship – a clear statement of the supremacy of the two gods as distributors of good and ill fortune, worshipped above all other gods. There is no reason to doubt that an ancient conception of a dualistic origin of the world did underlie the fundamental beliefs of the early Slavs and that the two deities mentioned by Helmold reflect this opposition. We are inclined to believe that Chernebog does echo the existence of an old khtonic god, possibly the same as VolosNeles, and need no longer be expelled from the Slavic pantheon. However, the limited amount of comparatively late historical and ethnographic material does not allow us to assert that the early Slavs – centering their religious beliefs around the worship of two opposing deities, hypostatized as a black and a white god – reached a level of religious dualism that can be viewed as a religio-historical phenomenon. (ZNAYENKO, 1993)

There are many proverbs and sayings that have to do with form characteristics and emotions. Straight: honest, easy, good, docile, obedient, calm, fair.
Lakoff and Johnson (1999)