9861. 'It shall be square when doubled' means that which is righteous and perfect. This is clear from the meaning of 'square' as that which is righteous, dealt with in 9717. The reason why that which is also perfect is meant is that the breastplate was doubled, and that which is doubled implies all aspects of good and all aspects of truth. What is on the right side implies the good from which truth springs, and what is on the left implies the truth springing from good, 9495, 9604 (end), 9736, thus also the two perfectly joined to each other. This accounts furthermore for the meaning of 'two' as things joined together, 8423, also every single aspect of them, 9166, and their completeness as well, 9103.

9717. 'Square shall the altar be' means that which for this reason is righteous. This is clear from the meaning of 'square' as what is righteous, dealt with below; and from the meaning of 'the altar' as what is representative of the Lord and of the worship of Him, so that 'square shall the altar be' means what is righteous within the Lord, and consequently within worship. Worship is called righteous when the good and the truth contained within it spring from the Lord and not from the person, for the Lord alone is the source of that which is righteous, 9263. The meaning of 'square' as what is righteous has its origin in representative signs in the next life. There forms of good present themselves as round shapes, and forms of good belonging to the external man, which are called righteous acts, as square shapes. Truths and right ideas however present themselves as linear and triangular ones. So it is then that 'square' means what is righteous, as does the squareness of the altar of incense, Exodus 30:2; also the squareness of the breastplate of judgement when doubled, Exodus 28:16; as well as the new Jerusalem's being square-shaped, Revelation 21:16. The new Jerusalem there is the Lord's New Church which will take the place of the one that is ours at the present day, its external good, which is righteous, being meant by 'square-shaped'.