Ibn Hazm said:
I have never seen Shaytan use a worse trick, or an uglier or a more foolish one, than when he puts two phrases onto the tongues of those who follow him. The first is when someone excuses his own evil deed by alleging that someone has done the same to him. The second is when someone makes light of doing evil today because he did evil yesterday, or he does wrong in one sense because he has already done it in another. 
Reflection: Pondering this quote will make you realize that much evil today, is because of false concepts put in our minds by Shaytan. The first one mentioned, is justifying evil done to others by the evil done to you. One person might insult another in a discussion and the other person reacts by insulting him back. This is so common in our times, and are one of the things we were warned against by the Prophet(ﷺ):
Abdullah ibn Amr reported: The Messenger of Allah(ﷺ) said, “Verily, one of the worst sins is that a man curses his own parents.” It was said, “O Messenger of Allah, how can a man curse his own parents?” The Prophet said, “He abuses the father of another man and then that man abuses his father and mother.” 
This hadith shows us how the Prophet(ﷺ) warned against actions that could produce a bad consequence, because the person whose parent are insulted, could feel justified to insult back. On a side note, notice how the Companions(ra) was surprised that a person could actually curse his own parents. I truly wonder if we would have even thought about asking the same question, in our age of “Teenage Rebellion”.
The other thing mentioned from Ibn Hazm is likewise relevant, because it shows the fine balance between fear and hope. A Muslim should always balance his perception of Allah by fearing His punishment, but also by realizing that Allah is forgiving if he falls short. You will find people who have too much of one and not the other. They might have so much fear of Allahs punishment, that they become hopeless and condemn themselves. So if they sin, they will keep sinning because they already did so much wrong and feel hopeless. In this sense, fear is like the example of the whip and the animal. The whip can be necessary to drive the animal forward, but if you keep beating it, it will eventually give up and lie down. So fear should be used to drive yourself forward in times of laziness and to change your course when faced with temptation. But if you start thinking your efforts are wasted and Allah will punish you anyway, the cure is to reflect on Allahs mercy and be hopeful of His forgiveness.
The correct mindset:
- Know that any insults or harm done against you, will be in your favor on the Day of Judgement. Your response to the injustice done against you will only increase your status, if you respond in the best way. If you pay it back with evil, you really aren’t very different from the one who did wrong to you in the first place.
- If you happen to sin, don’t become hopeless and tell yourself “Now I’ve done this, I might as well do this because I’m such a terrible person.” This is from Shaytan. You’re human, you make mistakes. Your father, Adam(as), slipped as well, and lost Paradise as a consequence, but his repentance was accepted by his Lord so he reclaimed what he had lost.
- Realize that Shaytan will do anything to make you deceive yourself. He will place false beliefs in your mind about what you’re entitled to, what justifies something, how terrible your actions are and your worth as a Muslim. The more you listen to this, the more he will lead you astray. You need to learn Islams perspective on these questions, by studying your Deen and asking scholars who know about the challenges of our time and society. Only then will you be able to find balance.
 Ibn Hazm, Al-Akhlaq wa’l-Siyar (English translation: “Morals and Behaviour”)
 Sahih al-Bukhari