Why was I not taught this until yesterday?
Learning about Jewish traditions sure does help understanding Christianity. I encourage you to look at the following web site at what the cups at passover mean paying particularly close attention to the 3rd cup.
Chosen People Ministries
Then there is the Jewish tradition of the cup at a wedding engagement. The father of the groom, the groom, the father of the bride, and the bride get together. The fathers discuss the brides price. Then once they agree on an amount, the groom poors a cup of wine and offers it to the bride. If she accepts the covenant, she drinks from the cup.
Think about that the next time you take communion. When you drink of HIS cup, you are his wife. You are signaling that you are making a commitment to HIM.
Oh, there is more, and I can't teach it all to you, so please look it up for yourself. There is also this web site that speaks about the Jewish betrothel Rebecca at the Well Foundation.
Have a BLESSED DAY!