Question:I have been trying to find out the why's of 'the fruit of the vine'. I understand and have read about the Passover. I think I understand the meaning of the Lord's Supper in relation to the Passover. I know why the bread is represented to be Jesus' body, and that Jesus said he was the Bread of Life. And his blood is represented by the fruit of the vine, which is grape juice. But why grapes? Was this a part of the Passover, or did Jesus choose it from his era as being a drink that was common then? Was it easier to obtain? I don't understand this part.
Jesus selected two things to help us remember his death: unleavened bread and fruit of the vine. "And as they were eating, Jesus took bread, blessed and broke it, and gave it to the disciples and said, "Take, eat; this is My body." Then He took the cup, and gave thanks, and gave it to them, saying, "Drink from it, all of you. For this is My blood of the new covenant, which is shed for many for the remission of sins. But I say to you, I will not drink of this fruit of the vine from now on until that day when I drink it new with you in My Father's kingdom" (Matthew 26:26-29).
As you pointed out, the bread represents Jesus' body and the fruit of the vine (grape juice) represents his blood.
Why grape juice? I would suspect that it is because it looks a bit like blood. "Binding his donkey to the vine, and his donkey's colt to the choice vine, he washed his garments in wine, and his clothes in the blood of grapes" (Genesis 49:11). Grape vines are something which grows in most parts of the world and it was readily grown in Israel. Unfermented grape juice was a part of the Passover meal (nothing with yeast was allowed in the house at Passover (Exodus 12:15)).