The Purpose of the Law（律法的用处）

In the letter to the Galatians, apostle Paul has clearly explained that one cannot be made righteous by keeping the law.  But what then is the purpose of the law?  In this passage, Galatians 3:15-29, let us understand the purpose God has intended for the law. 在加拉太书里，使徒保罗已经很清楚的解释，人是不可以靠律法称义的。那么，我们自然就会问"律法的用处是什么呢 ？"让我们听加拉太书3章15-29节解释律法的用处。