Arcana Coelestia #61
61. Everything that has to do with cognitions of faith is called spiritual, and everything that has to do with love to the Lord and towards the neighbour is called celestial. The former belong to man's understanding, the latter to his will.
Jeremiah 31:31-33
31
Behold, the days come, says Yahweh, that I will make a new covenant with the house of Israel, and with the house of Judah:
32
not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they broke, although I was a husband to them, says Yahweh.
33
But this is the covenant that I will make with the house of Israel after those days, says Yahweh: I will put my law in their inward parts, and in their heart will I write it; and I will be their God, and they shall be my people: