יחזקאל, פרק מ״ד, פסוק כ״ה

Priests are bound by strict laws of purity, generally forbidden from coming into contact with the dead. The primary approach among commentators is that this standard is directed at the regular priest rather than the High Priest, establishing a rule for the entire priestly community [מנחת שי]. A priest must not intentionally defile himself by being near a corpse [מצודת דוד]. However, clear exceptions are made for immediate family members. A priest is permitted to become impure for his father, mother, son, daughter, brother, and an unmarried sister [מצודת דוד, ביאור שטיינזלץ].

Commentators explore why this specific group of relatives forms an exception to the strict rules of priestly holiness. One perspective looks to the future, noting that even when priests eventually adopt the heightened strictness and caution normally reserved for a High Priest, they will still become impure for these family members. The reason is that mourning and becoming impure for close relatives is a Commandment. No amount of added strictness or pursuit of extra holiness can ever justify canceling a Commandment [מלבי״ם].

Alongside this, there is a profound spiritual reality behind the permission. The souls of close family members are deeply connected and intertwined. They are compared to a single flame illuminating two separate vessels. When a relative passes away, the inner flame of the surviving priest naturally dims. This profound loss leaves him in a state of internal, natural impurity. Because this spiritual impact has already taken hold within him, the Torah allows him to physically defile himself for his loved one [אהבת יהונתן]. Once the period of impurity ends and the priest separates from the deceased, he cannot immediately resume his sacred duties. He must undergo a process of counting seven days and completing a purification ritual to return to his holy status [אברבנאל, צאינה וראינה].