ויקרא, פרק ח׳, פסוק כ״ז

The ordination ceremony of the priests reaches a physical and symbolic peak of dedication. The person bringing the offering places the breads and the various parts of the sacrifice directly into the palms of the new priests, and together they perform a unique waving motion before God [ביאור שטיינזלץ].

While it is generally understood that the sacrifices themselves were waved [פירושי רד צ הופמן], or perhaps the hands of the priests holding the offerings [ביאור שטיינזלץ], another perspective suggests a highly unusual physical act. According to this view, Moses physically lifted and waved Aaron and his sons themselves, much like Aaron would later do when dedicating the Levites [אבן עזרא, ביאור שטיינזלץ].

The mechanics of this waving involved Aaron and his sons, who were the owners of the sacrifice, carrying the offering together [ביאור יש״ר]. Moses, serving as the acting priest at that moment, placed his hands underneath the hands of Aaron and his sons to wave the offering alongside them [ביאור יש״ר, תורה תמימה, מלבי״ם]. Alternatively, some suggest that Aaron and his sons placed their hands on top of Moses's hands [פירושי רד צ הופמן].

This specific process breaks the standard rules established for future generations. Normally, when multiple partners bring a single sacrifice, they do not wave it together. Having multiple hands involved creates a physical barrier that invalidates the action, as the law requires a single, unified waving motion rather than several parallel ones. Consequently, the standard practice is for a single representative to wave the offering on behalf of all partners [תורה תמימה, מלבי״ם, פירושי רד צ הופמן].

The reason for the unusual involvement of both Aaron and his sons together was to serve as a teaching model for specific future laws. By placing his hands underneath theirs, Moses demonstrated the proper procedure for the offering of a suspected adulteress, where the priest must place his hand under hers. Furthermore, other exceptional details of this event, such as waving certain animal parts separately, were designed to teach the specific waving procedures for a leper and to establish the foundational rules for waving sacrifices in general [תורה תמימה, מלבי״ם].