Old Testament law is a common point of attack by unbelievers. It is obvious that it is no longer in force, but the fact that it is no longer in force makes some unbelievers claim the Bible is contradictory.
I want you to imagine a book of architectural history. You turn to page 30 and see a building in its infant stages. Only one floor has been constructed, and there is a scaffolding in place. Skip forward a few pages and on page 35, you see the finished building, all 5 floors. But no scaffolding! Oh, what a contradiction! Clearly this can't be the same building!
But it is. It's the same building, minus the scaffolding, because the scaffolding is a temporary structure designed to aid in the construction of a building. It is never intended to be a part of the building itself, it's just there so the building can be completed. Once the building is complete, there is no need for the scaffolding.
Old Testament law is just that: A scaffolding (or, as Paul put it, the law was our tutor until Christ came, but when He came, we are no longer under a tutor). It is anything but a contradiction that the law is no longer in force. The law has served its purpose, it hasn't been abrogated, abolished, or changed. It was necessary to get us to the Gospel, but now the Gospel is here, we don't need that law any more. Now, we're under a new law.