The trespass offering was to atone for specific transgressions
where restitution was possible, such as
sins of ignorance, usually connected with fraud.
For example, if the worshipper had unwittingly cheated another,
a ransom that was equal to the same value of the amount taken
plus one-fifth would be given to the priest in advance.
Then the same amount would be repaid to the former property owner.
He therefore repaid twice the amount of what he had taken plus 40 percent.
The trespass offering was also prescribed in the cases of healed lepers in
Leviticus 14:12,
since leprosy was considered as a wrong to the congregation as a whole.
In this offering, the sacrifice was always a male (generally
a ram, which was never used as a sin offering).
The blood was thrown on the corners of the altars, like that
of the burnt offering.
More...