מדרש על ישעיהו 65:8

Rabbi Simon began: "Thus said Hashem: As, when new wine is present in the cluster, One says, “Don’t destroy it; there’s good in it,” So will I do for the sake of My servants, And not destroy everything (Isaiah 65:8)". A certain pious man went out from his vineyard on Shabbat and saw one cluster of grapes and said a blessing upon it. He said: "This cluster is deserving", and so he was blessed by it. Thus is said: ""Thus said Hashem: As, when new wine is present in the cluster".