Did the Law remove sin from people?
No. The Law was added because of sin, but it did not take sin away from people. Instead, it exposed and showed them their sin, making clear what is right and wrong. Paul writes in Romans 3 that the Law speaks to those under it, namely Israel.
Les explains that after the promises to Abram, God gave the Law because man had to understand what is right and what is wrong, and man did not seem to get it. The Law was added because of sin; it did not take sin away from people, it merely showed them their sin. Les then points to Romans chapter 3, verses 19 and 20, where Paul writes that whatsoever the Law says, it says to them who are under the Law—and that was Israel.
Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.