The dedication of Jerusalem's newly rebuilt wall was a meticulously planned public and legal ceremony designed to formally sanctify the city's expanded borders. To achieve this, a special procession was organized, featuring the nation's leaders, the Jewish court, and the priests.
Nehemiah brought the leaders of Judah directly up onto the wall itself, utilizing dedicated walking paths built along its top [רלב"ג, מצודת דוד]. Marching directly on top of the structure, rather than simply walking beside it, served a specific legal purpose: it formally sanctified the actual thickness of the wall and its windows [מלבי"ם].
At the center of this grand event were two great thanksgivings. Commentators offer different views on the nature of this detail. One perspective suggests these were two groups of Levites and singers who stood to praise God in song [אבן עזרא, רס"ג]. Because the city still faced the threat of lingering enemies, brave warriors armed with swords accompanied these singers for protection [רס"ג]. However, the primary approach among commentators is that these were two physical thanksgiving loaves used to encircle and sanctify the city. They are described as "great" because the ceremony specifically utilized the leavened loaves from the thanksgiving offering, which are significantly larger than the unleavened breads included in the same sacrifice [מצודת דוד, מלבי"ם].
The massive procession of the crowd then began moving [אבן עזרא]. The marchers initially turned to the right, heading south toward the Dung Gate [רש"י, שטיינזלץ]. At this stage in the journey, the group descended from the top of the wall and continued their march on the ground in front of the gate [מצודת דוד].
The full route of the march involved a complex geographic and legal arrangement, as the participants and the thanksgiving breads split into opposite directions. The ceremony began at the Valley Gate on the western side of the city. There, the two complete sets of thanksgiving loaves were presented. Half of the loaves from each set were given to the group marching south, and the other half went to the group marching north. This ensured that each procession carried portions from both original offerings. The two groups then encircled the city from opposite sides until they finally reunited on the eastern side of Jerusalem [מלבי"ם].