Hi Blik, I believe Psalm 119:1-2 meant the same thing when it was written to OT believers as it does to NT believers today.
Psalm 119
1 How blessed [How HAPPY] are those whose way is blameless,
Who walk in the law of the LORD.
2 How blessed [How HAPPY] are those who observe His testimonies,
Who seek Him with all their heart.
The opening verses of Psalm 119 are referring to the life of OT "believers" (and of sanctification/of living the Christian life of NT believers today, as well). When Paul refers to the Law of Moses as a strict "
schoolmaster" in Galatians 3, he is referring to its use in bringing people to faith for the first time, OT & NT (because it clearly shows us our need for a Savior). So Psalm 119:1-2 has little, if anything to do with the Apostle's teaching in Galatians 3:24-25, because the Law has a very different use than that in the life of someone who is already a believer.
This may be prove to be useful:
THE THREEFOLD USE OF THE LAW
by R.C. Sproul
Every Christian wrestles with the question, how does the Old Testament law relate to my life? Is the Old Testament law irrelevant to Christians or is there some sense in which we are still bound by portions of it? As the heresy of antinomianism becomes ever more pervasive in our culture, the need to answer these questions grows increasingly urgent.
The Reformation was founded on grace and not upon law. Yet the law of God was not repudiated by the Reformers. John Calvin, for example, wrote what has become known as the “Threefold Use of the Law” in order to show the importance of the law for the Christian life.1
The first purpose of the law
is to be a mirror. On the one hand, the law of God reflects and mirrors the perfect righteousness of God. The law tells us much about who God is. Perhaps more important, the law illumines human sinfulness. Augustine wrote, “The law orders, that we, after attempting to do what is ordered, and so feeling our weakness under the law, may learn to implore the help of grace.”2 The law highlights our weakness so that we might seek the strength found in Christ. Here the law acts as a severe schoolmaster who drives us to Christ.
A second purpose for the law is the restraint of evil. The law, in and of itself, cannot change human hearts. It can, however, serve to protect the righteous from the unjust. Calvin says this purpose is “by means of its fearful denunciations and the consequent dread of punishment, to curb those who, unless forced, have no regard for rectitude and justice.”3 The law allows for a limited measure of justice on this earth, until the last judgment is realized.
The third purpose of the law is to reveal what is pleasing to God. As born-again children of God, the law enlightens us as to what is pleasing to our Father, whom we seek to serve. The Christian delights in the law as God Himself delights in it. Jesus said, “If you love Me, keep My commandments” (John 14:15). This is the highest function of the law, to serve as an instrument for the people of God to give Him honor and glory.
By studying or meditating on the law of God, we attend the school of righteousness. We learn what pleases God and what offends Him. The moral law that God reveals in Scripture is always binding upon us. Our redemption is from the curse of God’s law, not from our duty to obey it. We are justified, not because of our obedience to the law, but in order that we may become obedient to God’s law. To love Christ is to keep His commandments. To love God is to obey His law.
Summary
1. The church today has been invaded by antinomianism, which weakens, rejects, or distorts the law of God.
2. The law of God is a mirror of God’s holiness and our unrighteousness. It serves to reveal to us our need of a savior.
3. The law of God is a restraint against sin.
4. The law of God reveals what is pleasing and what is offensive to God.
5. The Christian is to love the law of God and to obey the moral law of God.