Discharges

[Lev. 15:2] Speak unto the children of Israel, and say unto them, When any man hath a running issue out of his flesh, because of his issue he is unclean.
This involves the laws pertaining to a zov (if a man has discharge from his body he is unclean and can contaminate other). Being the effects of licentiousness, they properly come within the notice of the legislator, and the very stringent rules here described, both for the separation of the person diseased and for avoiding contamination from anything connected with him, were all calculated not only to prevent contagion, but to discourage the excesses of licentious indulgence. One could become unclean by touching a zov or even his clothing or mattress. A zov had to immerse himself in a mikveh and remain unclean until evening. On the 7th day he must immerse himself as well as his garments to be ritually clean.
Vessel of earth - it is thought that the pottery of the Israelites, like the earthenware jars in which the Egyptians kept their water, was unglazed and consequently porous, and that it was its porous ness which, rendering it extremely liable to imbibe small particles of impure matter, was the reason why the vessel touched by an unclean person was ordered to be broken.
13-14 like a leprous person he underwent a week’s probation, to make sure he was completely healed. Then with the sacrifice prescribed, the priest made atonement for him, that is, offered the oblations necessary for the removal of his ceremonial defilement, as well as the typical pardon of his sins.
An individual was considered unclean even if he had as few as 2 discharges. The two offerings, one a sin offering and the other a burnt offering had to be brought the 8th day after the discharges. The offerings were to be either turtledoves or pigeons. The sin offering was to atone for the sin that caused the affliction and the burnt offering was to show gratitude to Hashem for being cleanse.
19-33 the uncleanness of women, if a woman has an issue - though this, like leprosy, might be a natural affection, it was anciently considered contagious and entailed a ceremonial defilement that typified a moral impurity. This ceremonial defilement had to be removed by an appointed method of ceremonial expiation, and the neglect of it subjected any one to the guilt of defiling the Tabernacle, and to death as the penalty of profane temerity.
This involves the laws pertaining to a special bath (a ritually impure women because of her monthly period.) According to Halakhah, sexual intercourse between husband and wife is strictly forbidden during this time for at least seven days thereafter. Even other physical contact between them was avoided so much so that the wife slept in a separate bedroom. After seven clean days she immersed herself, after dark in a mikveh to attain the state of ritual purity. There involves the laws concerning to a zovah (a ritually impure woman who contaminates others.) When a zovah becomes healed of an impurity, she must bring two offerings, one for the sin offering and one for the burnt offering.
31-33. The divine wisdom was manifested in inspiring the Israelites with a profound reverence for holy things; and nothing was more suited to this purpose than to debar from the Tabernacle all who were polluted by any kind of uncleanness, ceremonial as well as natural, mental as well physical. The better to mark out that people as His family, His servants and priests, dwelling in the camp as in a holy place, consecrated by His presence and His Tabernacle, He required of them complete purity, and did not allow them to come before Him when defiled, even by involuntary or secret impurities, as a want of respect due to His majesty. And when we bear in mind that G-d was training a people to live in His presence in some measure as priests devoted to His service, we shall not consider these rules for the maintenance of personal purity either too stringent or too minute. (Thess. 4:4).