When the Bible talks about a "multitude," it is generally talking about truth -- concepts and ideas. When it talks about a "great" amount or "greatness," it is generally talking about love, delight and affection. That's because "multitude" implies many individual parts, and ideas tend to come in collections of individual facts and thoughts, while "greatness" implies one large thing, and loves tend toward unity and wholeness. "Fullness" brings the two concepts together, meaning either an abundance or a completeness of both good desires and true ideas held by a person or a group functioning as a church. And obviously when "fullness" is in reference to the Lord it means all truth and all goodness. Fullness can also be used in the negative; the Lord will bring a church down and build up a new one when the old one has become filled with evil and falsity in "the fullness of time," which can also have reference to the completion of other stages in spiritual life.