Did the Law Make David Righteous?

While reading 1 Kings, I found a passage that essentially called David righteous because He always did right and followed the Law:

Behold, I will tear the kingdom out of the hand of Solomon and give you ten tribes  (but he will have one tribe, for the sake of My servant David and for the sake of Jerusalem, the city which I have chosen from all the tribes of Israel), because they have forsaken Me, and have worshiped Ashtoreth the goddess of the Sidonians, Chemosh the god of Moab, and Milcom the god of the sons of Ammon; and they have not walked in My ways, doing what is right in My sight and observing My statutes and My ordinances, as his father David did. Nevertheless I will not take the whole kingdom out of his hand, but I will make him ruler all the days of his life, for the sake of My servant David whom I chose, who observed My commandments and My statutes; but I will take the kingdom from his son’s hand and give it to you, even ten tribes. But to his son I will give one tribe, that My servant David may have a lamp always before Me in Jerusalem,the city where I have chosen for Myself to put My name (1 Kings 11:31-36).

Now, I think there are three ways to interpret this.

1. David always followed the Law.
2. David did a pretty good job following the Law.
3. David was credited the righteousness as if he did follow the whole Law.

I do not think the first two work. For one, David sinned a ton of times. He murdered Uriah the Hittite, conducted a census, lied, and married a plethora of wives (something that Deut 17:17-18 explicitly forbids for kings).

So, David lived a life not of a sin here or there, but constant and persistent sin. Jesus Christ said that we cannot divorce, because we are one flesh with only one spouse. He said that when someone who is unmarried marries a divorced person, he by necessity commits adultery because of the preceding. This means that David essentially committed adultery his whole adult life.

Would you consider a President of the United States a righteous man if he was a murderer, liar, and serial adulterer? Then, why is David, the King of Israel, any more righteous?

The Scripture says of Job that he “was blameless, upright, fearing God and turning away from evil” (Job 1:1). In this sense, David did right and followed God’s Law because though he was worthy of blame, by faith in God he was blameless. Though his ways were crooked, he feared God, repented from evil, and was so upright.

Following God’s Law is not the following of rules, but a life typified by repentance and faith, like that of David. And his, by any standard, would otherwise be a rotten, wicked life. In fact, his last words were a charge to his son Solomon to murder Shimei the son of Gera the Benjamite for the sake of revenge (1 King 2:8).

Despite all his flaws, without sacraments nor perfect obedience to the Law, David was righteous because of his faith. Hence, it is this faith that in God’s eyes that can take a rotten man like David and make it as if he followed the whole Law.