The Lord tells Moses to send out of the camp everyone with a skin disease, a bodily discharge or defilement from a dead body, so that they do not defile the place where God dwells. The Israelites obey. The point is not to reject people but to protect the holiness of the camp while their uncleanness lasts.
Then the Lord gives a law about wrongs: when someone sins against another, he also acts unfaithfully toward the Lord, and he must confess his guilt and repay what he owes, adding a fifth, to the person he wronged. If that person has no relative to receive the payment, the restitution belongs to the Lord and goes to the priest, along with the ram of atonement. The holy gifts of Israel belong to the priests.
The rest of the chapter deals with the case of jealousy. If a man suspects his wife has been unfaithful and there are no witnesses, he brings her before the priest with an offering of barley flour. The priest sets her before the Lord, writes the curses of the oath and washes them into holy water mixed with dust from the floor of the tabernacle. The woman takes the oath and drinks the water. If she is guilty, she will suffer the stated effect; if she is innocent, she will be free and able to bear children. The husband is free of guilt either way.