One of the senses that children display from their conscience is about justice. When they play or in other situations they come out with the statement, "That's not fair!" We too feel the same at different times when we see a culprit goes free, the wicked prosper and the godly suffer, we don't get what we deserve, we are punished for something we didn't do, somebody doesn't forgive us even when we apologise, others don't understand us, etc. One typical question that people ask is, "If God is almighty and also loving, why does He permit so much evil in this world?" Many such questions reflect the underlying issue, "Can we find justice on the earth?"
When God chose in His sovereign wisdom to create us in His image including a little bit of sovereignty in ourselves – our free will – He knew He was opening up a possibility for evil to come into the world. He knew that men and women might choose to do wrong. Starting from Adam and Eve, that is what we people have brought into the world. So injustice forms a large part of our experience here. We wish it wasn't, but it is there.
Under the Law, external justice was given such a great importance that people were permitted to take an eye for an eye, etc. (Ex.21:24,25). When Jesus taught about the shift of focus from the external to the internal in the new covenant, He said that we ought to rather suffer injustice than demand justice for ourselves, forgiving even our enemies. Isn't that what He was saying in the passage in Mt.5:38-45, rather than giving us actual rules to obey such as turning our cheek?
By this He was not prohibiting us from seeking justice or helping others to find justice, but telling us indirectly that it would not be always possible for us to get justice in this world. We ought to reckon with this and be prepared to suffer if need comes. It involves overlooking faults, forgiving sins, not taking offence easily, not keeping an account of wrong suffered (1Co.13:5), etc., when it concerns ourselves (while at the same time taking up for others who are being oppressed). This kind of behaviour comes from Christian maturity which we need to press towards.
If we are hung up on demanding justice for ourselves in every situation, we will never be able to grow up in our spiritual life. We have then forgotten that it was because God let His mercy overtake His justice that we have been forgiven (Jas.2:13). As those who have been shown mercy that we didn't deserve, we ought to show mercy to the others even when they don't deserve it. There will be a time when God will sit in judgment and pass orders with a balanced mixture of justice and mercy. Till then let us remember that it is likely we don't have this balance in our judgment and refrain from acting out of our pride, hardness of heart and ignorance. Let us place more attention to learning how to show mercy than to demand justice from others. Compassion is more important to God than sacrifices (Mt.9:13).