Mountain
The Lord's love is the sun of heaven, and it is natural for us to look above ourselves to the sun of this world in thinking about the Lord. It follows, then, that to be closer to the Lord we would climb into the highest places -- and indeed, people have been worshiping on mountains for ages. In fact, even steeples on modern churches are symbolic mountains. It makes sense, then, that a mountain in the Bible represents love to the Lord, the highest, purest love we human beings can experience. Mountains can also represent the desire for good that comes from the love of the Lord. Hills, meanwhile, represent a love of other people and a caring for them, and when "mountains" is used in the plural it generally represents both loves.
Arcana Coelestia # 707
707. From here down to verse 5 the details are almost identical with those stated in the previous chapter, with only minor changes; and the same applies to what comes after that. Anyone who is not aware of the internal sense of the Word is bound to conclude that it is mere repetition of the same thing. Similar instances occur in other parts of the Word, especially the Prophets, where the same matter is expressed in other and different words. And sometimes the matter is taken up again and described once more. The reason for this, as stated already, is that the two faculties with man of will and understanding are totally different from each other, and that the Word deals with both separately. This is the reason why repetitions exist. That the same applies here will be clear from what follows.