Q. Someone asked me why we mark the four promises in Exodus chapter 6 with four cups of wine. Why not four of something else, e.g. apples?
“I will take you to be Mine” is, for example, greater than “I will take you out from under the burdens of Egypt”. The promises have to be marked by something that grows in enjoyment.
Four apples, for instance, would not do. You would like the first one or two but by the fourth you would have had enough. Wine, on the other hand, not only “gladdens the heart of man” (Psalm 104:15) but augments your enjoyment with each cup.