Charles Ellicott Commentary Leviticus 13:1

"And Jehovah spake unto Moses and unto Aaron, saying," — Leviticus 13:1 (ASV)

And the Lord spoke to Moses and Aaron. — Since the laws of leprosy primarily concerned the priests, who were to examine the symptoms and decide whether they indicated the disease or not, the Lord addressed the regulations to Aaron as well as to Moses. The leprosy discussed in this and the following chapters consists of three general classes:

1. Leprosy of man (Leviticus 13:2–46);
2. Leprosy of garments (Leviticus 13:47–59);
3. and leprosy of houses (Leviticus 14:33–57).

When a man shall have in the skin of his flesh. — In discussing the leprosy of man, the lawgiver enumerates six different circumstances under which it may develop. The first circumstance presented in Leviticus 13:2-6 is its developing without an apparent cause. Therefore, it was instructed that if anyone should notice a rising or swelling in the skin of his flesh, he should be taken to the priest. Since the description of these symptoms is very concise and needs to be specified more minutely for practical purposes, the spiritual guides of Israel, who had to explain the law to the priests during the Second Temple and who came into personal contact with this disease, defined them as follows:

A rising. — This is a swelling, or swollen spot.

Or bright spot. — This is a bright or glossy pimple. However, these symptoms, when indicative of leprosy, respectively assume one of two colors: a principal or a subordinate color. The principal color of the rising spot is like that of an eggshell, and the secondary one resembles white wool; while the principal color of the bright pimple is white as snow, and the subordinate resembles plaster on the wall.

Then he shall be brought unto Aaron. — The following rules prevailed during the Second Temple regarding the examination of the patient. Although anyone may examine the disease except the patient himself or his relations, yet the priest alone can decide whether it is leprosy or not, because the law declares that the priests must decide cases of litigation and disease (Deuteronomy 21:5); therefore, the patient must be brought unto Aaron, etc.

But although only the priests can pronounce the patient clean or unclean, even if he is a child or a fool, yet he must act upon the advice of a learned layman in these matters. If the priest is blind in one eye, or is weak-sighted, he is disqualified from examining the disease. The inspection must not take place on the Sabbath, nor early in the morning, nor in the middle of the day, nor in the evening, nor on cloudy days, because the color of the skin cannot be properly ascertained at those times of the day; but it must take place in the third, fourth, fifth, seventh, eighth, and ninth hours.