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.

1895. 'She had an Egyptian servant-girl' means the affection for knowledge. This is clear from the meaning of 'a servant-girl' and from the meaning of 'Egypt'. Sarai, who is the mistress or lady, represents and means truth allied to good, as stated already. Truth allied to good is in the genuine sense intellectual truth, but rational truth comes below this and so is inferior. The latter is born from knowledge and cognitions that have been made living by means of an affection corresponding to them. Because this affection is part of the exterior man, it ought to be subservient to intellectual truth, which resides inmostly, in the way that a servant-girl is subservient to her mistress or a maid to the lady of - the house. That affection therefore is what is represented and meant by 'the servant-girl Hagar'.

[2] No one can have much understanding of anything said about these matters until he knows what intellectual truth is in the genuine sense and also in what way the rational is born, namely from the internal man as the father, and from the exterior or natural man as the mother. Unless the two are joined together nothing rational ever comes into being. The rational is not born from knowledge and cognitions, as people suppose, but from the affection for them, as becomes clear merely from the fact that nobody can possibly become rational unless some delight in or affection for such knowledge and cognitions burns within him. The affection constitutes the maternal life itself, while the celestial and spiritual within that affection constitute the paternal life. Consequently it is the degree and the quality of a person's affection that determine the degree and the quality of the rationality that is developed in him. In themselves facts and cognitions are nothing other than things that are dead, or instrumental causes, which are made alive by the life that belongs to affection. This is how everyone's rational man is conceived. The reason why the servant-girl was Egyptian and why that fact is mentioned is that 'Egypt' means knowledge, as has been shown already in 1164, 1165, 1186, 1462,