From a historic and halachic perspective, it seems that a basic component of every new king’s inauguration involved anointing the king with oil. Yet, surprisingly, though the Torah explicitly outlines in detail how the mitzvah of appointing a new king is to be carried out, the verse makes no mention of the anointment with oil.
Moreover, the first Jewish king anointed with oil was Shaul, who was appointed by the prophet Shmuel. We know, however, that Yehoshua had the halachic status of a king, yet he received his appointment through semichah—by Moshe’s “leaning his hands upon him.” Granted, the authority to transmit the Torah is conferred through semichah, but the authority to rule the nation is conferred through anointment. So why did Moshe not anoint Yehoshua with oil?
The Rambam defines the purpose of the Jewish monarch: His purpose and intent shall be to elevate the true faith and to fill the world with justice, destroying the power of the wicked and waging the wars of G‑d. For the entire purpose of appointing a king is to execute justice and wage wars.
As is evident from the Rambam’s words, the Jewish king’s role is not only to govern and lead the nation’s material affairs, but primarily to promote the ways of the Torah. As such, though the king’s reign over the nation is his exclusively, at the same time the monarchy is in essence an extension of the Sanhedrin—the body of authority entrusted with transmitting the Torah.
Yet the monarchy and the Sanhedrin remain distinct branches of government, and each is conferred its power differently and independently.
The reign of Yehoshua was the exception. On the one hand, Yehoshua exclusively was tasked with transmitting the Torah to his generation—a power normally granted to the Sanhedrin (as a group). At the same time, Yehoshua was also king, charged with implementing the Torah’s teachings within the capacity of his kingship.
It was therefore unnecessary for Yehoshua to be anointed with oil. Since Yehoshua held both branches of Jewish leadership exclusively, the semichah that endowed him with his spiritual authority—of which the monarchy is merely an extension—was sufficient to establish his kingship as well.
Accordingly, we can understand why the Torah does not explicitly mention the requirement of anointing a new king with oil. For the Torah’s ideal form of monarchy, as embodied by Yehoshua, is one in which the king is the Torah authority as well, in which case anointing with oil is unnecessary.
—Likkutei Sichos, vol. 23, pp. 190–197
