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.

940. The majority in this hell are Jews who have been disgustingly avaricious, and when they come among other spirits their presence is detected as the stench of mice. While on the subject of Jews let some account of their cities and of the robbers in the desert be given to show how wretched their condition is after death, that is to say, the condition of those who have been disgustingly avaricious and who, because of the arrogance bred into them, have looked down on others and imagined that they alone were the elect.

[2] As a result of their having conceived and confirmed for themselves during their lifetime the false notion that they would enter into Jerusalem and would possess the Holy Land - not wishing to know that by the New Jerusalem is meant the Lord's kingdom in heaven and on earth - a city appears to them when they enter the next life on the left side of Gehenna and a little to the front. Into the city they stream in solid masses. That city however is muddy and stinking, and is therefore called the filthy Jerusalem. There they rush in all directions through its streets, ankle-deep in sludge and mud, wailing and lamenting as they do so. This city, including its streets, they see with their eyes; it is a representation to them, as in clear daylight, of the kind of people they are. I have indeed seen that city frequently.

[3] A swarthy person coming out of this filthy Jerusalem once appeared before me, the gate seeming to be opened. Roving around him, chiefly on his left side, there were stars - in the world of spirits stars roving around a spirit mean falsities; the meaning is different when the stars are not roving around. He came up to me and pressed himself to the upper part of my left ear which he seemingly touched with his mouth so as to speak to me. No sound came from him as from others when he spoke; instead he spoke within himself, yet his speech was such that I heard and understood. He said that he was a Jewish rabbi and had been in that muddy city for a long time. He also said that the streets of the city were nothing but sludge and mud wherever you went, and that there was nothing else but muck to eat.

[4] I asked why it was so that he, being a spirit, should desire to eat at all. He said that he did eat, and when he desired to eat, he was offered nothing other than muck, which he moaned about exceedingly. Saying that he had not found Abraham, Isaac, and Jacob, he asked what he ought therefore to do. I told him certain facts concerning these three, and added that he was seeking them in vain. Even when he found them, I said, they could be no possible help whatever. In addition to mentioning other deeper matters I said that nobody at all ought to be sought except the Lord alone, who is the Messiah whom during their lifetime these Jews had rejected with contempt. I went on to say that He rules the whole heaven and the whole earth, and that help comes from none other. He asked eagerly and repeatedly, 'Where is He?' I said that He is found everywhere, and that He hears and knows us all. But at that point some other Jewish spirits dragged him away.