Great question! In saying “the law was only for the Jews” I assume you are thinking of passages which clearly teach that the law (i.e. the Ten Commandments) was given to the nation of Israel through Moses. We read in Exodus 34:27-28, “And the LORD said to Moses, ‘Write THESE WORDS, for according to the tenor of THESE WORDS I have made a COVENANT WITH YOU AND WITH ISRAEL.” In John 1:17 the Apostle John said, “For THE LAW was given through Moses, but GRACE and truth came through Jesus Christ.” For 1500 years (from the time Moses received the Ten Commandments to the time that Jesus came to preach the GRACE of God) Israel was “under the law.” But why was the Law given to Israel and not to the Gentile nations? To answer this, I will quote a passage which teaches us the primary reason the Law was given to the Jews, but it will also help to answer your question. In this passage God is teaching us that both Jews and Greeks “are all UNDER SIN,” that is, all are lost sinners and are in bondage to sin, and that it is the Law that has proven this solemn fact. The passage I’m referring to is Romans 3:9-20 but due to our limited space, I will only quote verses 9-12 and 19-20:

“What then? Are we (Jews) better than they (Gentiles)? Not at all. For we have previously charged both Jews and Greeks that they are all under sin. As it is written: ‘There is none righteous, no, not one; There is none who understands; There is none who seeks after God. They have all turned aside; they have together become unprofitable; there is none who does good, no, not one…Now we know that whatever THE LAW says, it says to THOSE WHO ARE UNDER THE LAW, that EVERY MOUTH may be stopped, and ALL THE WORLD may become guilty before God. Therefore by the deeds of the law no flesh will be justified in His sight, for BY THE LAW IS THE KNOWLEDGE OF SIN.”

We see here that Israel was given the Law as a “sample of the human race” and their failure to “keep the Law” proved that no one could keep the law and thus “all the world is guilty before God.” To illustrate this, a farmer had just purchased a 1,000-acre field with the hope of growing sugar beets on it. In order to see if the soil is suitable for growing sugar beets, he takes 50 acres and plants the seeds, only to find out come harvest time that the soil is not good for growing sugar beets. In doing so, he now knows the whole field (all 1,000 acres) is NO GOOD. Likewise, God’s testing of Israel resulted in proving that “there is none righteous, no, not one.” The law was not given to the Jews to see if they could obey it; the law was given to prove they COULD NOT KEEP IT and to give them “knowledge of their sin.” This “test” proved we are all sinners, even if we were never formally “under the Law.” As we saw in Romans 3:9, we are “all under sin” and the law has proven this in God’s testing of Israel.

Let’s close on a positive note. Romans 3:21-24 goes on to say, “But now the righteousness of God APART FROM THE LAW is revealed, being witnessed by the Law and the Prophets, even the righteousness of God through faith in Jesus Christ, to ALL and on ALL who believe. For there is no difference; for all have sinned and fall short of the glory of God, being JUSTIFIED FREELY BY HIS GRACE through the redemption that is in Christ Jesus.” The Law could not save us (it only revealed our sin and condemned us), but faith in Jesus Christ and His finished work on the cross has indeed SET US FREE! It declares us RIGHTEOUS and has set us “free from the law” which could never justify us. I would encourage you to read and meditate on Galatians Chapter 3. The Apostle Paul is writing mainly to Gentiles who had been saved but some were being tempted to put themselves “under the law.” He shows them what we learned in Romans Chapter 3, that the Law could only CONDEMN (CURSE) US, but that “Christ has redeemed us from the curse of the law, having become a curse for us” (verse 13).  (DO)  (696.5)