The first altar mentioned in the Word was the one built by Noah after he came out of the ark, after being saved from the great flood. On that altar, he sacrificed clean animals to the Lord.

Mountains represent the Lord because of their height; we need to raise our thoughts above worldly things when "talking" with the Lord. An altar is a small artificial mountain. When it's used in worship, it can call to mind this raising of thought. The fire and smoke that rise from an altar are symbolically being sent to the Lord.

Most altars were made from unhewn stones. Stones represent truths. Unhewn stones - ones that have not been shaped by men - represent truths from the Word, truths that have not been adulterated.

The clean beasts to be sacrificed represent good things, charitable acts done because they are right. The clean birds represent thoughts about doctrine and actions, and about what is right. Presenting these things is an acknowledgment that we have them from the Lord, and a giving thanks to Him for them.

In the Israelitish Tabernacle, the altar of burnt offering represented the acknowledgment of good and the altar of incense that of truth. For this reason this larger altar, which was outside by the door, was made of brass which signifies natural good, while the altar of incense was made of gold, which signifies love to the Lord from whom comes truth.

4145. 'Because you longed greatly for your father's house' means a longing to be joined to Divine good flowing in down a direct line. This is clear from the meaning here of 'father's house' - that is, Isaac and Abraham's house - as good flowing in along the direct line of descent. For 'house' means good, see 2233, 2234, 3652, 3720; 'father' too means good, 3703; 'Isaac' means the good of the Rational, 3012, 3194, 3210. In addition to this 'Abraham together with Isaac' represents Divine good flowing along the direct line of descent, and 'Laban' parallel good or good which does not flow in along the direct line, 3665, 3778. Parallel good or that which does not flow in along the direct line is the good which has been called intermediate good, for this good derives very much from things that are worldly which seem to be good but are not. Good flowing in along the direct line comes immediately from the Lord or else from the Lord by way of heaven as an intermediary; it is also Divine good separated from the kind of worldly good just mentioned.

[2] With everyone who is being regenerated good is at first intermediate good, for the purpose that it may serve in the introduction of genuine goods and truths. But once it has served that use it is separated; and that person is guided towards good which flows in along the direct line of descent. So a person who is being regenerated is perfected gradually. For example: a person who is being regenerated believes at first that the good which he thinks and which he does begins in himself, and also that he earns some reward, for he does not yet know, or if he does know does not comprehend, that good is able to flow in from some other source. Neither does he know of or comprehend any other possibility than that he should be rewarded because he does it of himself. If he did not believe this at first he would never do anything good. But by this means he is introduced not only into the affection for doing good but also into cognitions concerning good and also concerning merit. And once he has been guided in this way into the affection for doing good he starts to think differently and to believe differently. That is to say, he starts to think and to believe that good flows in from the Lord and that he merits nothing through good which he does from the proprium. And when at length true affection lies behind his willing and doing of what is good he rejects merit altogether and indeed loathes it, and he is moved by an affection for good for the sake of what is good. When this state is reached good is flowing in down a direct line.

[3] Take as another example conjugial love. The good which comes first and is introductory is good looks, or good manners, or outward compatibility, or similarity of social class, or aspiration. These forms of good are the first intermediate ones of conjugial love. After this comes the joining together of minds (animus) in which one wills as the other does and finds delight in doing that which is pleasing to the other. This is the second state, and although those initial forms of good are still present they are no longer kept in view. Finally there follows a uniting involving celestial good and spiritual truth. That is to say, one believes as the other believes, and one is moved by an affection for good as the other is moved. When this state is reached both together experience the heavenly marriage, which is a marriage of good and truth, and so experience conjugial love since conjugial love is nothing else. At the same time the Lord is flowing into the affections of them both as into a single affection. This is a good which flows in down a direct line, whereas the previous kind of good which had flowed in down an indirect line had served as the means of introduction to this good.