The ultimate and highest form of leave-taking is leaving God for GOD—leaving your notion of God for an experience of That which transcends all notions. – Meister Eckhart

Purity, symbolized in various forms across many spiritual disciplines, is a state one must attain by emptying oneself of all preconceptions of the divine to become ready to receive the Spirit of God for "an experience of That which transcends all notions," making way for divine conception.