God told Moses that the time had come for Aaron to leave this world. Moses prayed all night, agonizing: "How can I tell my brother his life is ending?" God answered with a promise—He would not hand Aaron's soul over to the angel of death.
Moses devised a plan. Normally, princes waited at Aaron's door each morning. On this day, Moses reversed the order—he, Eleazar, and all the princes rose early to wait on Aaron instead. When Aaron came out and saw Moses standing among them, he asked: "Why have you changed your custom?" Moses could not answer yet. "I cannot speak until we leave this place."
As they walked, Moses placed Aaron in the middle—the position of honor. The Israelites noticed and whispered to each other: "The Holy Spirit has been removed from Moses and given to Aaron." They rejoiced, because they loved Aaron even more than Moses—he was the man who loved peace and pursued it. Moses led them to a cave on Mount Hor, where he found a prepared bed, a burning lamp, and a table. He asked Aaron to remove his priestly garments, one by one, and hand them to his son Eleazar. When Aaron stood stripped of his vestments, Moses told him to lie down, close his eyes, and stretch out his hands and feet.
According to the Chronicles of Jerahmeel, a 12th-century Hebrew chronicle translated by Moses Gaster in 1899, Aaron asked in that final moment: "Is this what troubled you all day?" Moses said: "Yes." And Aaron died by the kiss of God—peacefully, without the angel of death, exactly as God had promised. Moses and Eleazar came down from the mountain weeping. When the people saw Eleazar wearing his father's garments and Aaron nowhere in sight, they understood. All Israel mourned Aaron for thirty days.