The number "two" has two different meanings in the Bible. In most cases "two" indicates a joining together or unification. This is easy to see if we consider the conflicts we tend to have between our "hearts" and our "heads" -- between what we want and what we know. Our "hearts" tell us that we want pie with ice cream for dinner; our "heads" tell us we should have grilled chicken and salad. If we can bring those two together and actually want what's good for us, we'll be pretty happy. We're built that way -- with our emotions balanced against our intellect -- because the Lord is built that way. His essence is love itself, or Divine Love, the source of all caring, emotion and energy. It is expressed as Divine Wisdom, which gives form to that love and puts it to work, and is the source of all knowledge and reasoning. In His case the two aspects are always in conjunction, always in harmony. It's easy also to see how that duality is reflected throughout creation: plants and animals, food and drink, silver and gold. Most importantly, it's reflected in the two genders, with women representing love and men representing wisdom. That's the underlying reason why conjunction in marriage is such a holy thing. So when "two" is used in the Bible to indicate some sort of pairing or unity, it means a joining together. In rare cases, however, "two" is used more purely as a number. In these cases it stands for a profane or unholy state that comes before a holy one. This is because "three" represents a state of holiness and completion (Jesus, for instance, rose from the tomb on the third day), and "two" represents the state just before it.

1823. 'Take a three year old heifer, and a three year old she-goat, and a three year old ram' means things that are the representatives of the celestial things of the Church. This is clear from the meaning of these same animals in sacrifices. Nobody in his right mind can believe that the various animals that used to be sacrificed meant nothing but sacrifices, or that an ox and a young bull or a calf had the same meaning as a sheep, kid, and she-goat, and these the same as a lamb, and that a turtle dove and fledgling pigeons had similar meanings; for in fact each creature had its own specific meaning. This becomes quite clear from the fact that under no circumstances was one kind of animal offered instead of another, and from the fact that it was explicitly stated which creatures were to be used in the daily burnt-offerings and sacrifices, and which on the sabbath and at festivals; which creatures were to be used in free-will, votive, and communion offerings; which ones were to be used in expiations of guilt and sin; and which in purifications. This would never have been the case if some specific thing had not been represented and meant by each animal.

[2] But as to the specific meaning of each kind, this would take too long to explain here. Here it is enough if one knows that celestial things are meant by the animals and spiritual things by the birds, and that some specific celestial or spiritual thing is meant by each kind of animal or bird. The Church itself, and everything to do with the Jewish Church, was representative of such things as constitute the Lord's kingdom, where nothing but that which is celestial or spiritual exists, that is, nothing but that which belongs to love and faith, as also becomes quite clear from the meaning of clean and useful beasts, dealt with in 45, 46, 142, 143, 246, 714, 715, 776. And because in the Most Ancient Churches beasts meant celestial goods, in the Church existing at a later time when purely external, though representative, worship was highly esteemed and approved of, those beasts became representatives.

[3] Because the state of the Church is the subject here and because the nature of its state in the future is foretold, Abram was shown the same visually by means of similar representatives, exactly as recorded here. Yet quite apart from this, such things are nevertheless meant in the internal sense, as anyone may know and contemplate. For what would have been the need to take a three year old heifer, a three year old she-goat, a three year old ram, a turtle dove and a fledgling, and to divide them in two parts and to lay them out so, unless each single thing had carried a spiritual meaning? But what these details mean becomes clear from what follows below.