Offering sacrifice doesn't mean anything if it doesn't produce this regarding sin,Israel was deep in sin and rebellion. Their sacrifices were in vain. They meant nothing.
whoso confesseth and forsaketh them shall have mercy. Pro.28:13
And the teaching here isn't, "Keep committing the same sin and just bring another ram for forgivenes."Question, if a Jew offered a ram for a trespass offering for sin, would that offering bring forgiveness of sin?
19:21 And he shall bring his trespass offering unto the Lord, unto the door of the tabernacle of the congregation, even a ram for a trespass offering.
22 And the priest shall make an atonement for him with the ram of the trespass offering before the Lord for his sin which he hath done: and the sin which he hath done shall be forgiven him.
The reason why sacrifice was offered was so people would sin no more.