Many different names for the Lord appear in the Bible, and they all have different shades of meaning. “Jehovah” is the actual name of God, and was regarded as so holy that people of the Biblical Jewish church dared not say it aloud. As such, it refers to the Lord's essence, which is love itself -- perfect, infinite, divine love. “God” is more external -- other nations had gods -- and thus represents divine truth, which is the full expression and form of the love that makes up the Lord's essence. Using them together, then, represents the Lord as to both aspects -- His love and its expression.