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.

4280. In that lower sense the words 'he touched the hollow of Jacob's thigh' mean where conjugial love is joined to natural good. This is clear from the meaning of 'the hollow of the thigh' as the place where conjugial love is linked to it, see above in 4277. The reason why the place where it is linked to natural good is meant is that it is the place where the thigh is joined to the feet. 'The feet' in the internal sense means natural good, see 2162, 3147, 3761, 3986.

[2] As regards 'the thigh' meaning conjugial love and 'the feet' natural good, that is one of those realities known in the past which have grown old and died. The Ancient Church, which existed in an age of representatives and meaningful signs, was extremely well acquainted with these meanings, such knowledge of them constituting their intelligence and wisdom. Indeed it constituted the intelligence and wisdom not only of those who belonged to the Church but also of those outside the Church, as becomes clear from the oldest books written by gentiles and from the stories in them which are nowadays called myths - for meaningful signs and representatives spread from the Ancient Church to those gentiles. With these also 'the thighs and loins' meant that which belonged to marriage, and 'the feet' things that were natural. The origin of this meaning of 'the thighs and the feet' lies in the correspondences of all the members, organs, and viscera of the human being with the Grand Man, which - that is to say, such correspondences - are being dealt with now at the ends of chapters. The correspondences with the thigh and the feet will be discussed again further on, where actual experience will be used to corroborate that their meaning is as indicated above.

[3] These things are bound to seem like enigmas at the present day because, as has been stated, that knowledge has grown very old indeed and died. Yet how far that knowledge excels other types of knowledge becomes clear from the consideration that the internal sense of the Word cannot possibly be known without that knowledge, as well as for the reason that the angels present with man perceive the Word according to that sense. It becomes clear also from the consideration that by means of that knowledge man is provided with communication with heaven. And what is unbelievable, the internal man himself does not think in any other way; for when the external man understands the Word according to the letter the internal man does so according to the internal sense, though while living in the body a person is not at all conscious of doing so. This becomes particularly clear from the fact that when anyone enters the next life and becomes an angel he has no need to learn the internal sense but knows it instinctively, so to speak.

[4] What conjugial love is which is meant by 'the thighs' and also by 'the loins', see 995, 1123, 2727-2759; and conjugial love is the basic love of all loves, 686, 3021. Consequently people who have genuine conjugial love in them also have celestial love, which is love to the Lord, and spiritual love, which is charity towards the neighbour. For this reason the expression 'conjugial love' is used to mean not only that love itself but also all celestial and spiritual love. These kinds of love are said to be joined to natural good when the internal man is joined to the external, that is, the spiritual man to the natural - that joining together of them being meant by 'the hollow of the thigh'. The fact that with Jacob and his descendants in general no such conjunction existed will be evident from what follows, for this is the subject dealt with here in the internal historical sense.