Badal means to separate, divide, or make a distinction. God uses this verb in creation when He separates light from darkness and waters above from waters below (Genesis 1:4, 6, 7). It is also used for the priestly distinction between the holy and the common, the clean and the unclean.
Separation is at the heart of holiness in the Old Testament. Badal underlies the entire structure of the Levitical law, which taught Israel to distinguish between sacred and profane. The Levites were separated to serve God (Numbers 8:14), and Israel was separated from the nations (Leviticus 20:24). This word carries the theological weight of election — God calls a people apart for Himself. The New Testament equivalent is found in being 'in the world but not of it.'