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.

5639. 'And Joseph saw Benjamin with them' means the discernment by the celestial of the spiritual that the spiritual intermediary was present with the truths. This is clear from the meaning of 'seeing' as understanding and discerning, dealt with in 2150, 2807, 3764, 4567, 4723, 5400; from the representation of the ten sons of Jacob - to whom 'with them', that is, the ones whom Joseph saw Benjamin with, refers - as the truths within the natural, dealt with in 5403, 5419, 5427, 5458, 5512; and from the representation of 'Benjamin' as the intermediary, dealt with in 5411, 5413, 5443. The reason the expression 'spiritual intermediary' is used here is that the truths which are represented by 'the ten sons of Jacob' had now to be joined to truth from the Divine, which was 'Joseph'; but that joining together does not take place except through an intermediary that is a spiritual one. Therefore immediately after that intermediary had been recognized, Joseph told the man over his house, 'Bring the men to the house, and slaughter and prepare [an animal]; for the men will eat with me at midday', meaning that they would be brought in and joined to him because they were accompanied by the intermediary.

[2] A further brief statement needs to be made about what the spiritual compared with the natural is since the majority living in the Christian world do not know what the spiritual is. They are so ignorant of what it is that when they hear the term they are at a loss, saying to themselves, What the spiritual is, no one knows. Essentially the spiritual existing with a person is his actual affection for what is good and true, loved for its own sake and not for any selfish reason, as well as an affection for what is right and fair, likewise loved for its own sake and not for any selfish reason. When a person has inward feelings of delight and pleasure, and more so if feelings of blessedness and bliss flow from them, they constitute the spiritual present with him, which does not come to him from the natural world but from the spiritual world or heaven, that is, from the Lord by way of heaven. This then is the spiritual which, when it reigns in a person, influences and so to speak gives colour to everything he thinks, wills, or does, and which causes his thoughts and acts of will to partake of what is spiritual, till at length these too become spiritual qualities present with him when he passes from the natural world into the spiritual world. In short, the spiritual consists in an affection stirred by charity and faith, that is, an affection for what is good and true, and in the delight and pleasure, and even more so in the blessedness and bliss that flow from them, which are feelings residing with a person inwardly and making him someone truly Christian.

[3] The majority in the Christian world are ignorant of what the spiritual is for the reason that they make faith, not charity, the essential virtue in the Church. Consequently, since the few who do bother about faith give little if any thought at all to charity or know what charity is, and since therefore they have no knowledge or any perception of the affection characteristic of charity, an affection that is not present in them, they cannot possibly know what the spiritual is. This is especially so at the present day when scarcely any charity exists with anyone, for now is the final period of the Church. But it should be recognized that in a general sense the spiritual means an affection both for what is good and for what is true, which is why heaven is called the spiritual world and the internal sense of the Word is called the spiritual sense. But more specifically what is essentially an affection for good is called the celestial, while that which is essentially an affection for truth is called the spiritual.