God is Not Just
God is not just. This may shock many people, but there are plenty of such examples in the Bible.
We have all sinned and deserve the punishment of death, but God did not kill us all! Instead He let His Son die for our sins so we can live. That is NOT just!
Amazingly, His Son taught the same thing to His disciples.
Then Peter came and said to him, Lord, what number of times may my brother do wrong against me, and I give him forgiveness? Till seven times? Jesus says to him, I say not to you, till seven times; but till seventy times seven. Matthew 18:21-22
This means when a brother does something wrong against us, we have to forgive him and let him go as long as he asks for forgiveness. That is NOT fair!
Prophet Jonah apparently felt the same way, so he initially refused to warn wicked Nineveh of God's coming judgement.
And God saw their works, that they (Nineveh) turned from their evil way; and God repented of the evil that he had said that he would do unto them; and he did it not. But it displeased Jonah exceedingly, and he was very angry. Jonah 3:10, 4:1
Why didn't God just do justice and wipe out all the wicked people? I believe this is the difference between Righteousness and Justice.
What is Righteousness?
Righteousness is doing what is right in the eyes of God. But this does not always means justice. Israel has rebelled against Yahweh many times, but Yahweh still took care of them because He insisted to do the right thing in keeping His covenant with Abraham, Issac and Jacob. As Peter said, God is "not willing that any should perish, but that all should come to repentance" (2 Peter 3:9). Therefore, besides justice, God's righteousness also include mercy, wisdom, patience, and many other factors for the highest good of His creations.
Why is God's Righteousness Important?
We are Created to Rule
We are living in a world created by God. How can anyone continue to live a healthy life here without knowledge of God's principles upon which everything is operating? As human beings, it is even more important for us to learn God's righteousness. Why? Because Man are created in the image and likeness of God. To do what? To "have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creeps upon the earth" (Genesis 1:26). We have been created to RULE, but most people have forgotten about that!
How can anyone rule successfully in a Kingdom created by God if he does not know what is right in the eyes of God? Solomon was only able to rule over Israel successfully at his young age because he asked God for wisdom. After he fell into idolatry, his kingdom quickly fell apart.
Laws Given through Moses
God first taught us His righteousness by giving us His Laws through Moses. Through studying God's Laws, we learn what is right and wrong in the eyes of God, and different people can finally live together in peace by submitting themselves to the same set of rules and values, which include no murder, no adultery, no theft, etc.
However, although many people have come to understand intellectually what is right and wrong, most people are still unable to keep all of God's commandments because of our sinful nature! As Paul said,
But I see another law in my body, working against the law of my mind, and making me the servant of the law of sin which is in my flesh. Romans 7:23
Rebirth through the Blood of Christ and Holy Spirit Guidance
To overcome this sinful nature, God in His wisdom has already prepared for us a way of rebirthing through the Blood of Jesus Christ. With a sinless new spirit, we can now learn the righteousness of God as new born babes by studying the Word and following the guidance of the Holy Spirit.
Even though this learning process may mean numerous trials, sufferings, mistakes and persecutions, the Law can now be written in our hearts. There is finally a path for us to make our ways back to Heaven, and to make ourselves ready candidates to enter into God's New Kingdom.
And I will put my Spirit within you, and cause you to walk in my statutes, and you shall keep my judgments, and do them. And you shall dwell in the land that I gave to your fathers; and you shall be my people, and I will be your God. Ezekiel 36:27-28
I will put my laws into their hearts, and in their minds will I write them; And their sins and iniquities will I remember no more. Hebrews 10:16-17