...Ill never do it again".
The scapegoat would atone for all the sins in the Torah:
for the serious ones, and for light ones;
for those done purposefully, and for those done accidentally;
for those the sinner was aware of, and for those he was not aware of -
- as long as the sinner did teshuvah.
But if he didnt do teshuvah, the scapegoat would only atone for light sins.
John 1:29 KJV
The next day John saw Jesus coming toward him, and said, Behold! The Lamb of God who takes away the sin of the world!