Righteousness starts with the vertical relationship with God through our Lord Jesus Christ which gives us the right to stand unashamed before a Holy God. It is a "right standing" before God. This is only done if we are walking in the atonement of Christ's sacrifice for our sins and in God's Truth and Spirit.
Among men we have the horizontal relationship of righteousness. It is the quality of life demonstrated by those who live up to the established norms in a relationship. In other words, they seek to do right by another person.
Justice starts with the vertical relationship whereby God must punish sin. God determined who was right in the court case of holiness and found only the Lord Jesus Christ to be innocent. All those who are "in Christ" have been declared "justified" because Christ took their sin and punishment upon Himself. Those outside of Christ have been declared guilty and already under God's condemnation. In the horizontal we see the judicial process of determining who is right in a case of law. The justice system of the court was established to determine and free the innocent and punish the guilty.
In human trafficking and human slavery we find that the one guilty of trafficking is unrighteous both before God and before man. They cannot stand unashamed before a Holy God and they are not doing right by another person's life.
The trafficker is guilty of injustice before God and before man. In the court case before God they are found to be outside of Christ and His commands, and outside the character and Word of God. Before man the trafficker is guilty of injustice in the fact that between them and the victim they violated the case of humanity, dignity, and self-will. Therefore, injustice is done and must be punished to the fullest extent of the law.