'Salt' symbolizes the desire of truth and good to be conjoined with each other. So, a salt can conjoin water, which corresponds to truth, with oil, which corresponds to good.

Salt can also have a negative meaning. 'Lot's wife becoming a statue of salt' signifies all the good of truth being vastated, or laid waste, in the church that Lot represented. In that story, Lot's wife represented a form of 'truth' that turned itself away from 'good,' and looked instead to doctrinal matters. Because 'salt' can signify vastation, and 'cities' signify doctrinal aspects of truth, in old times they sowed cities with salt when they were destroyed to prevent them from being rebuilt, as in Judges 9:45

(Notae: Arcana Coelestia 10300)

1996. 'I will make My covenant between Me and you' means the union of the Internal Man, which was Jehovah, with the Interior Man. This is clear from the meaning of 'a covenant' as a joining together, for as often as a covenant between Jehovah and man is mentioned in the Word, nothing else is meant in the internal sense by a covenant than the Lord's being joined to man. The covenants made so many times between Jehovah and the descendants of Jacob had no other representation. As this point has been confirmed in Volume One, in 665, 666, 1023, 1038, 1864, it would be superfluous to do so again here. The Lord's Internal Man was Jehovah because He was conceived from Him, while the Interior Man is represented here by Abram. Consequently 'the covenant between Me and you' means the union of the Internal Man, or Jehovah, with the Interior Man, and so with the Lord's Human Essence.