After a long period of spiritual neglect, a historic decision is made to renew the Passover sacrifice and unite the Israelites around a pilgrimage to Jerusalem. This initiative begins with a firm resolution to broadcast a call across all the cities of Israel [מצודת דוד, ביאור שטיינזלץ]. However, this decree also carries the absolute weight of a royal command. Because the sages of the generation disagreed with King Hezekiah's decisions, he is forced to assert his governmental authority to enforce the plan. Messengers are dispatched immediately to ensure the people do not treat the upcoming prohibition of leaven lightly [מלבי״ם].
The royal proclamation is spread from the southern boundary of Beersheba all the way north to Dan. Highlighting these specific borders emphasizes that the message is deliberately targeted at the territory of the Ten Tribes. The ultimate goal is to unite every faction of the nation in the observance of the Passover [רש״י].
Such a sweeping declaration is necessary because the proper observance of the festival has been largely abandoned. The primary approach among commentators is that this neglect was a matter of time and frequency; many years had passed without the Israelites properly observing the Passover, making it urgent to remind and encourage them [רש״י, מצודת דוד, רלב״ג]. The spiritual decay was so severe that even those familiar with the laws treated them as mere theory rather than a practical duty [ביאור שטיינזלץ].
In contrast, another perspective suggests the underlying issue was not about the passage of time, but rather the demographic majority of the people. King Hezekiah worried that if Passover were held at its normal time while the nation remained ritually impure, only a small fraction of the population would attend. Under Jewish law, a minority of the nation is not allowed to offer the Passover sacrifice in a state of impurity, prompting the king to add a leap month to the calendar to allow time for purification. The sages, however, argued against this delay. They maintained that a "majority" is calculated only based on the people who actually enter the Temple courtyard, meaning there was no legal need to postpone the festival because of the broader nation's impurity [מלבי״ם].