Arcana Coelestia #6283
6283. 'And in them will my name be called' means that in them the essential nature of the good of spiritual truth from the natural will be present. This is clear from the meaning of 'one's name being called in another' as the essential nature of one in the other, dealt with in 1754, 1896, 2009, 3421; and from the representation of 'Israel' as the good of spiritual truth from the natural, dealt with above in 6277. And since they had within them Israel's essential nature they were accepted among the rest of Jacob's sons and became tribes, one the tribe of Manasseh, the other the tribe of Ephraim. Along with the rest - though excluding the tribe of Levi because it became the priesthood - they made up the twelve tribes when inheritances were allotted to them, as described in Joshua and also Ezekiel 48.
Apocalypse Revealed #358
358. Of the tribe of Issachar twelve thousand were sealed. This symbolizes goodness of life in those people who will be part of the New Heaven and of the Lord's New Church.
In the highest sense Issachar symbolizes the Divine good of truth and truth of good; in the spiritual sense, the conjugal love of heaven, which is one of goodness and truth; and in the natural sense, recompense. Here, however, it is goodness of life, because in this group Issachar is the third in order, and the third element in every group symbolizes the final one, which is the product of the first two, as an effect is of its causes. And the effect produced by spiritual love, which is love for the neighbor and symbolized by Simeon, operating through an affection for truth, which is symbolized by Levi, is goodness of life, which is Issachar. The name Issachar also comes from a word meaning payment (Genesis 30:17-18), thus recompense; and goodness of life has in it its own recompense.
Something of the kind is symbolized by Issachar, too, in Moses' blessing of him:
Rejoice, Zebulun, in your going out, and Issachar in your tents! They shall call peoples to the mountain; there they shall offer sacrifices of righteousness; for they shall suck the affluence of the sea and the hidden objects of the sand. (Deuteronomy 33:18-19)
In his father Israel's blessing of him (Genesis 49:14-15), however, Issachar symbolizes a merit-seeking goodness of life. See Arcana Coelestia (The Secrets of Heaven) 6388.