This is a biggie. “After Moses shattered the first set of tablets, he pleaded with G‑d to forgive the Jewish people. G‑d did forgive them, and instructed Moses to prepare two replacement tablets upon which G‑d would inscribe the Ten Commandments again.
[G‑d told Moses,] “I will inscribe on the [second set of] tablets the words that were upon the first tablets. . . . ” Deuteronomy 10:2
Moses shattered the first tablets when he saw that the Jewish people had fashioned the Golden Calf. These shattered tablets were kept in a special wooden box, which G‑d instructed the Jewish army to take with them whenever they went into battle. But how could the eternal testimony that the Jews had sinned by making the Golden Calf have been of any help – or of any merit – when they were risking their lives in battle?
Moses broke the tablets when he saw the Golden Calf because at that moment they became worthless. The Torah “flew” out of the tablets and returned to heaven, rendering them two “lifeless” stones. G‑d Himself had indeed carved them, but they were now nothing compared to what they had become when G‑d chiseled the Ten Commandments into them. Thus, the lesson of the shattered tablets is that we should never be satisfied with our inherent worth; we should always strive to maximize our potential.
The same lesson applies today. Rather than being content with past achievements, we must continually strive to fulfill our personal potential and our Divine mission, recognizing that without it, we are but a lifeless, shattered stone.1 Likutei Sichot, vol. 14, pp. 30–36.