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.

9742. 'On the south side, southwards' means that it dwells in the light of truth. This is clear from the meaning of 'the south, southwards' as a place where truth dwells in light, dealt with in 9642. The reason why the court lay on that side was that those who are in the court of heaven, that is, in the lowest heaven, are governed by the good of faith, and the good of faith comes into being through enlightenment provided by the light which comes from the Lord. The light which comes from the Lord is the truth of faith, and when this truth is integrated into the will it is called the good of faith. With those who are in the outer court a new will part is formed within the understanding part of their mind, 9596; and to enable it to be formed there it is necessary for those people to dwell in the light of truth. This explains why in relation to the dwelling-place the court was made 'on the south side, southwards'.