במדבר, פרק י׳, פסוק ה׳

Moving an entire nation through a desert required a massive logistical effort and a flawless communication system. To coordinate the journey, a precise sequence of sounds was broadcast to the Israelites, prompting the tribes to move in a highly organized procession.

The primary approach among commentators is that the signal to begin traveling was a specific three-part audio sequence. The core of this signal was a broken, trembling blast that conveyed a sense of sudden shock or agitation [שד״ל, ביאור יש״ר, ביאור שטיינזלץ]. This fragmented sound was sharply contrasted with a continuous, long blast [ביאור שטיינזלץ]. The instruction to sound the alarm inherently required blowing a steady blast first, followed by the trembling sound, and concluding with a second steady blast.

To ensure the people clearly understood the instructions, a sharp distinction was made between gathering the nation and initiating a journey. Calling the community together required only a simple, continuous blast. In contrast, moving the massive camps demanded the full three-part sequence. This separation proves that the steady blast and the broken alarm were completely distinct sounds, and the combined sequence served as the uniform signal for every camp to set out.

The first group to respond to this signal was the eastern division, which was the camp of Judah [חזקוני, ביאור שטיינזלץ]. This eastern group consisted of three distinct tribes marching under a single banner, functioning as a cluster of multiple camps rather than just one [אבן עזרא, ביאור יש״ר]. As these eastern tribes set out, they were directly accompanied by the individuals carrying the Tabernacle [ספורנו].

This staggered method of departure reveals a highly structured approach to their travels. The Israelites did not surge forward as a single block the moment the trumpets sounded. Instead, they moved in an orderly procession, with each designated camp waiting for its specific turn to begin the march [ברכת אשר על התורה].