To "go before" in the Bible means either to lead or to prepare, depending on context. When it is said of the Lord or things representing the Lord -- the Ark of the Covenant, an angel, the pillars of cloud and fire -- it means to lead. When it is said of other people -- John the Baptist, for example, was to "go before the face of the Lord" -- it means to prepare people for what is to follow.

(References: Arcana Coelestia 10399, 10508; The Apocalypse Explained 724 [7]; True Christian Religion 688)