דברי הימים ב, פרק ל׳, פסוק ג׳

The decision to delay the Passover sacrifice to the second month was driven by a combination of practical hurdles and strict requirements of Jewish law that made it impossible to observe the holiday during its original time in the first month of Nisan [רש״י, מצודת דוד].

The primary obstacle was the state of the priests. There were not enough pure priests who had finished preparing themselves to handle the heavy workload of processing the Passover sacrifices for the entire nation [רש״י, ביאור שטיינזלץ]. Even if the purification of the Temple itself had not run late, the sheer shortage of ready priests would have forced a delay regardless.

This situation highlights an important principle in Jewish law. The issue was not that every single priest was impure. If the entire priesthood had been impure, the sacrifice would not have been delayed at all. Instead, it would have been offered in a state of impurity, as the law dictates that only individuals are pushed off to a second Passover, not an entire community. There were indeed pure priests available, but their numbers were simply too small for the task. This specific situation, a severe shortage of pure priests rather than total impurity, is what permits the delay of the holiday [רלב״ג].

Beyond the priesthood, there was a second major challenge. The people themselves had not yet gathered in Jerusalem. The pilgrims had not arrived in time because a massive pilgrimage of this scale was a renewed tradition. It had been many years since such a gathering had taken place in the Kingdom of Judah, and even longer in the Kingdom of Israel. Because the people were unaccustomed to the practice, the logistics of organizing and completing the long journey took much more time than anticipated [ביאור שטיינזלץ].