In Exodus 3:12, this signifies a confirmation of the truth that the Divine proceeded from Himself. (Arcana Coelestia 6870)

(References: Arcana Coelestia 1039, Genesis 9:12, 9:13, 9:17)

1039. 'Which I give between Me and you' means conjunction of the Lord with man by means of charity. This is clear from what has just been stated about the covenant and the sign of the covenant. Actually 'the covenant' is the Lord's presence within charity, 'between Me and you' is conjunction resulting from that presence, 'giving' is bringing it about.