Leviticus 13 is the longest chapter in the book—a detailed medical manual for diagnosing skin diseases. The Targum Jonathan transforms it from clinical instructions into a color-coded diagnostic system, adding visual details the Hebrew Bible leaves vague.
The key addition: the Targum distinguishes between "whiteness like snow" and "whiteness like chalk." If the plague spot is white like snow and deeper than the surrounding skin, it is leprosy. If white like chalk and not deeper, the priest quarantines the person for seven days. This distinction does not exist in the Hebrew Bible, which uses a single word for white. The Targum creates a two-tier diagnostic framework based on shade.
Hair color becomes critical evidence. White hair "as the white of an egg" indicates old, established leprosy. Yellow hair "like a thin thread of gold" signals scalp leprosy. The egg-white and gold-thread comparisons are Targum additions, giving priests a visual reference standard for diagnosis.
The leper's social exile gets expanded with devastating detail. He must have "his clothes rent, and his hair shall be taken off, going to the shearer's, and his lips shall be covered." Then, "clothed like a mourner, and crying, as a herald, he shall say, Keep off, keep off from the unclean!" The doubled cry—"keep off, keep off"—and the comparison to a mourner are Targum additions that transform medical quarantine into a public ritual of grief.
The Targum also specifies that a leper must stay away from his wife: "to the side of his wife he must not come nigh." The Hebrew says only "he shall dwell alone, outside the camp." The Targum makes the marital separation explicit.
Even garments could contract leprosy—a sign that God's standards of purity extended beyond the human body. The Targum follows the Hebrew through elaborate inspection procedures for wool, linen, and leather—a reminder that in this worldview, holiness and disease could inhabit objects, not just bodies.