ויקרא, פרק ח׳, פסוק כ״ו

During the ordination ceremony of the priesthood, Moses prepares the wave offering. The basket of unleavened bread is positioned directly before God. This placement contrasts sharply with the animal sacrifices. Live animals were kept outside the courtyard until the exact moment of slaughter to prevent them from soiling the sacred space. The baked and sanctified breads, however, were brought directly into the Sanctuary well in advance [ביאור יש״ר, רד צ הופמן].

From this basket, three distinct types of baked goods are selected. The first is a round loaf of unleavened bread. Its circular shape is reflected in its Hebrew name, which shares a root with words describing circular motion [הכתב והקבלה], leading some to simply identify it as a standard loaf of bread [אבן עזרא, רד צ הופמן]. Special care was required for this specific loaf to ensure it remained unleavened. Because the dough was quite thick, it could easily rise if left unattended. This was not a concern for the other baked goods, such as the thin wafers or scalded dough, which do not leaven quickly [העמק דבר].

The second item is an oil bread. The primary approach among commentators is that this refers to a scalded dough, boiled in hot water and mixed with oil. It earned its name because it contained a uniquely large amount of oil. Of the total oil allocated for all the baked goods, half was distributed among the round loaves and thin wafers, while the remaining half was poured exclusively into this single type of bread [רש״י, מזרחי, גור אריה].

Once the breads are selected, they are carefully arranged for the wave offering. The rule for this ritual is that the bread must always rest on the very top of the animal portions [תורה תמימה, רד צ הופמן]. Beneath the breads lay the fats and the right thigh. The fats include both the actual layers of detachable fat and the most premium parts of the offering, such as the tail, since the finest portion of any item is conceptually referred to as its fat [ביאור יש״ר]. Underneath the fats rests the right thigh, which is the lower part of the animal's leg [הכתב והקבלה].

In standard peace offerings, this right thigh is given as a regular gift to the priests. However, during this specific ordination ritual, Aaron and his sons were still in the process of being initiated and were not yet considered full priests. Consequently, the thigh was not given to them to eat; instead, it was placed upon the altar as a dedicated portion entirely to God [ספורנו].