'The blood of the grape' signifies spiritual celestial good, which is the name given to the divine in heaven as it goes out from the Lord. Wine is called the 'blood of grapes,' to the extent that each signifies holy truth going out from the Lord. 'Wine' refers to the spiritual church, and 'blood' refers to the celestial church. This being the case, wine was partaken of in the holy supper.

(References: Arcana Coelestia 5118)