How to deal with injurias

Confucius lived in a cultural environment totally different from ours. Therefore, nowadays, we may not understand the correction intention of the words he spoke. One such example is an idiom which could be traced back to an incident related to him. The idiom is 「以德報怨」roughly translated as "with virtuous acts, we repay maltreatment". The background was not clear. It was recorded in the Analect that someone asked his opinion on this moral norm. Here is the full text.
或曰：以德報怨，何如？子曰：何以報德？以直報怨，以德報德。【論語‧憲問】
Somebody asked, "Repay maltreatment with virtue, what do you say?" Confucius said, "How then can we repay virtue? Repay maltreatment with justice, virtue with virtue."
Quidam ait: cum beneficiis retribuere simultates, quomodo? Confucius respondit: cum quo retribues beneficia? Utitor aequitate ad compensandas injurias, cum benefcio retribue beneficium. (Auctore P. Angelo Zottoli, S.J., 1879 CE)
In the bible reading today, we read a similar situation between Saul and David 1 Samuel 24.

Saul spent the latter half of his life chasing after the life of David because God had rejected him and anointed David the next king of Israel. It was not fair to David because he had no intention to replace Saul. David had been helping Saul in his military expeditions, killing Goliath and winning many battles. Saul was infuriated by the people who showered more praises on David than on him. He was jealous and David fled from his presence, without putting up any resistance.
It so happened that Saul led 3000 men to chase after David who hid in a cave with his men. Saul was exhausted and took a rest inside the same cave. Seeing that God had delivered Saul into their hands, David's men tried to persuade David to kill Saul.
And the men of David said to him, "Here is the day of which the LORD said to you, 'Behold, I will give your enemy into your hand, and you shall do to him as it shall seem good to you.'" Then David arose and stealthily cut off the skirt of Saul's robe (1 Samuel 24:4)
Even so, David's conscience smote him because he had cut off the skirt of Saul (1 Samuel 24:5).
He said to his men, "The LORD forbid that I should do this thing to my lord, the LORD'S anointed, to put forth my hand against him, seeing he is the LORD'S anointed."
So David persuaded his men with these words, and did not permit them to attack Saul. And Saul rose up and left the cave, and went upon his way (1 Samuel 24:6-7).
David still respected Saul as the Lord's anointed. When Saul left, David called out.
See, my father, see the skirt of your robe in my hand; for by the fact that I cut off the skirt of your robe, and did not kill you, you may know and see that there is no wrong or treason in my hands. I have not sinned against you, though you hunt my life to take it.
May the LORD judge between me and you, may the LORD avenge me upon you; but my hand shall not be against you (1 Samuel 24:11-12).
David left the avenge to the Lord. He would not take justice into his own hand. This itself is justice because if we take justice into our own hand, very likely, we will overdo. God knows the most appropriate way to avenge us on the wrongdoers. This is faith in God true to the sense. Confucius did not know God but he knew to repay injustice with justice, virtue with virtue. Though Confucius expounded a lot on virtue, he did not say as much on justice. Justice for him was what was appropriate. He knew the appropriate way to deal with man. I would say Confucius knew God, though he was unable to confess God.

Dear Lord, we are short-tempered. We tend to seek immediate fairness. You are wise. You know justice thoroughly. May we control our temper and learn true justice. Amen.