The vine is a symbol in the bible used for Israel. Studying the grape vine as a metaphor for Israel in the Old and New Testament shows us startling concerns that God had with the nation. The value of the grape vine was dependent on the quality of the grape. The vine itself was useless for any other thing than to be burned. Israel's value as a nation was dependent on their spiritual obedience and fruitfulness. Understanding this, you'll see how Jesus calling himself the true vine infuriated the religious leaders of his time.