Arcana Coelestia # 5737
5737. 'And his silver for grain' means the truth of good. This is clear from the meaning of 'silver' as truth, dealt with in 1551, 2954, 5658, and from the meaning of 'grain' as good, dealt with in 5295, 5410. For interior or spiritual truth, which goes forth from the internal celestial represented by 'Joseph', is the truth of good. For what the truth of good is, see just above in 5733.
Arcana Coelestia # 5410
5410. 'To buy grain from Egypt' means to make the good of truth its own through factual knowledge. This is clear from the meaning of 'buying' as making one's own, dealt with in 4397, 5374, 5406; from the meaning of 'grain' as the good of truth, dealt with in 5295; and from the meaning of 'Egypt' as factual knowledge, dealt with above in 5402.