Arcana Coelestia # 2109
2109. A son of thirteen years. That this signifies holy remains, may be seen from the signification of “ten,” as being remains (explained above, n. 576, 1988); and from the signification of “three,” as being what is holy (see n. 720, 901). Thus the number “thirteen,” being composed of ten and three, signifies holy remains. (That numbers in the Word signify actual things, may be seen above, n. 482, 487, 488, 493, 575, 647, 648, 755, 813, 893. What the remains with man are, has been stated above, n. 468, 530, 561, 660, 1050, 1906)
Genesis 17:14
14
The uncircumcised male who is not circumcised in the flesh of his foreskin, that soul shall be cut off from his people. He has broken my covenant."