עזרא, פרק ג׳, פסוק א׳

The return to the Land of Israel involved a massive migration, with the people likely arriving during the summer, the most practical season for undertaking long journeys [ביאור שטיינזלץ]. Upon their arrival, the Israelites dispersed to settle in their respective cities and ancestral lands [מצודת דוד, ביאור שטיינזלץ].

However, their time apart was brief. As the seventh month, Tishrei, drew near [רש״י, ביאור שטיינזלץ], a powerful sense of anticipation took hold. Rather than waiting for the official start of the new month, the people took the initiative. They began their journey back to Jerusalem a few days early, ensuring they would be settled and present in the city in time for the New Year and the sequence of festivals that followed [מלבי״ם].

Leaving their newly settled homes, the entire nation converged on Jerusalem in complete unity [רש״י]. This massive gathering was not a slow, disjointed migration. Instead, the event was marked by remarkable speed. The vast crowds traveled so swiftly and cohesively that it was as if a single person were making the journey to the city [אבן עזרא, מצודת דוד].