במדבר, פרק י״ט, פסוק ד׳

The preparation of the Red Heifer reaches its ceremonial and critical peak during the sprinkling of the blood. This action bridges the physical gap between the heifer's location outside the camp and the spiritual center of the Sanctuary, demanding both strict physical precision and deep mental concentration. Eleazar, the deputy to the High Priest, is selected for this task because the blood sprinkling constitutes the very core of the Commandment [חזקוני], though in future generations, a regular priest is fully qualified to perform it [תורה תמימה]. The priest must wear official priestly garments [רלב״ג, אדרת אליהו, מלבי״ם, העמק דבר]. Specifically, he wears plain white garments, even if the High Priest himself conducts the service. Similar to the service on the Day of Atonement, these white clothes focus the priest's mind entirely on purity. They deliberately strip away any elements of splendor and beauty from a ceremony whose entire essence is the burning and nullification of the animal [רלב״ג]. To further ensure the priest remembers the profound sanctity of the act—which carries the same strict laws as a sin offering—he is separated a week in advance into a designated chamber in the northeast of the Temple area as a constant reminder [תורה תמימה].

Unlike standard sacrifices meant for atonement, where blood is collected in a designated sacred vessel, the Red Heifer's blood is intended purely for purification. Therefore, the priest's own body serves as the vessel [מלבי״ם]. He receives the blood directly into the palm of his left hand and dips the index finger of his right hand into it [תורה תמימה, צפנת פענח, רש״ר הירש, אדרת אליהו, מלבי״ם]. He must gather a sufficient quantity of blood in his palm at one time to complete all seven required sprinklings [אדרת אליהו].

The sprinkling must be aimed precisely toward the entrance of the Sanctuary, located on the eastern side [ביאור יש״ר, ביאור שטיינזלץ, מלבי״ם]. During the Temple era, the priest stood far outside Jerusalem at the top of the Mount of Olives in the east, facing west toward the Sanctuary [רש״י, תורה תמימה]. Despite standing at a great distance and outside the designated boundaries of the camp, the priest is required to direct his gaze and maintain a clear, unobstructed physical view of the Sanctuary entrance [רש״י, רלב״ג, תורה תמימה, שפתי חכמים]. While the desert Tabernacle had no walls to block this view, in Jerusalem, the eastern wall of the Temple Mount was intentionally constructed lower than the others specifically to allow the priest this direct line of sight [משכיל לדוד, ברכת אשר]. If the priest fails to aim exactly toward the entrance, or if he performs the act without the proper mental intention, the entire process is rendered invalid [תורה תמימה, אדרת אליהו, רש״ר הירש].

The act of sprinkling is repeated seven times, but the priest cannot rely on a single dip of his finger. He must dip his finger into the gathered blood anew for each individual sprinkle [רלב״ג, רש״ר הירש, העמק דבר, מלבי״ם]. To guarantee that only fresh blood is used each time, he wipes his finger on the skin of the heifer between sprinklings. This wiped blood is later burned along with the rest of the animal [רלב״ג, רש״ר הירש]. The action itself must be a deliberate sprinkle, not merely thrown or allowed to drip [אדרת אליהו].

On an allegorical level, this entire process serves as a spiritual guide for a person seeking repentance. Blood, which shares a linguistic connection with the Hebrew word for money, symbolizes the Commandment of giving charity. Giving with one's finger implies that a person should distribute charity according to their personal capacity and means. Directing this action toward the Sanctuary alludes to supporting the prominent Torah scholars who sit in the study halls. Finally, performing the act seven times teaches that one should spread their charitable giving across all seven days of the week, securing continuous spiritual merit day after day [אדרת אליהו לר' יוסף חיים].