In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Firstly, Imaam Ibnul Qayyim [rahimahullaah] said:
The basis of Banee Aadam’s misguidance is as a result of ‘General Terms’ and ‘Ambiguous Meanings’ [i.e. terms & meanings which can either be utilised for truth or falsehood when not explained in detail and distinguished], especially if they come in contact with a confused mind, then how about when [evil] desires and misguided enthusiasm is added to that? Therefore, ask the One Who keeps the hearts steadfast [i.e. Allaah] to keep your heart firm upon His Religion and not allow you to fall into this darkness. [Ref A]
One of the general fundamental principles [in Islaam] is to know that words [or terms] are two types: Words that are mentioned in the Qur’aan and [authentic] Sunnah, therefore, it is obligated on every believer to affirm them – affirm what Allaah and His Messenger have affirmed, and negate what Allaah and His Messenger have negated. The words [or terms] affirmed by Allaah is truth and the ones Allaah negated are [negated] in truth, for indeed Allaah speaks the truth and guides to the straight path. The words [or terms] of the Sharee’ah are sanctified, and it is from perfection in knowledge that one seeks after the [sound meanings] which the Messenger [sallal laahu alayhi wasalam] intended by them, in order to affirm what he affirmed and negate the meanings he negated; for indeed it is obligated on us to believe and bear witness to everything he has stated and follow him in everything he has commanded. As for the words [or terms] that are neither found in the Qur’am and [authentic] Sunnah, nor did the Salaf hold a consensus regarding whether they are negated or affirmed, then it is not incumbent on anyone to agree with the one who negates them or affirms them until its intended meaning is explained. So, if its intended meaning agrees with the [revelation, commands, prohibitions etc] conveyed by the Messenger, it is affirmed; but if its intended meaning is in opposition to the [revelation, commands, prohibitions etc] conveyed by the Messenger, it is rejected. [Ref B]
Therefore, the statement ‘Two wrongs Don’t Make a Right’ cannot be used unrestrictedly, rather this statement should be uttered only when someone takes the law into his own hands.
Secondly, the only effective deterrent is the Sharee’ah of Islaaam. Shaikh Abdul Waahid Abu Khadeejah [hafidhahullaah] said:
Some Islamic countries such as Saudi Arabia and parts of Nigeria use Sharī’ah Law as the law of the land. These include death penalties for murder and drug trafficking, and amputation and removal of a hand for thieves who steal beyond a certain considerable sum. Even though these punishments exist, they are not used often because the crime rate in many Muslim countries is low. That is for two reasons: 1. The citizens are keen to live their lives in accordance to their Islamic faith, ethics and morals. 2. The threat of these punishments serve as strong deterrent against crimes. [Ref C]
Finally, Allaah [The Exalted] said:
يَـٰٓأَيُّہَا ٱلَّذِينَ ءَامَنُواْ كُتِبَ عَلَيۡكُمُ ٱلۡقِصَاصُ فِى ٱلۡقَتۡلَىۖ ٱلۡحُرُّ بِٱلۡحُرِّ وَٱلۡعَبۡدُ بِٱلۡعَبۡدِ وَٱلۡأُنثَىٰ بِٱلۡأُنثَىٰۚ فَمَنۡ عُفِىَ لَهُ ۥ مِنۡ أَخِيهِ شَىۡءٌ۬ فَٱتِّبَاعُۢ بِٱلۡمَعۡرُوفِ وَأَدَآءٌ إِلَيۡهِ بِإِحۡسَـٰنٍ۬ۗ ذَٲلِكَ تَخۡفِيفٌ۬ مِّن رَّبِّكُمۡ وَرَحۡمَةٌ۬ۗ فَمَنِ ٱعۡتَدَىٰ بَعۡدَ ذَٲلِكَ فَلَهُ ۥ عَذَابٌ أَلِيمٌ۬
وَلَكُمۡ فِى ٱلۡقِصَاصِ حَيَوٰةٌ۬ يَـٰٓأُوْلِى ٱلۡأَلۡبَـٰبِ لَعَلَّڪُمۡ تَتَّقُونَ
O you who believe! Al-Qisas (the Law of Equality in punishment) is prescribed for you in case of murder: the free for the free, the slave for the slave, and the female for the female. But if the killer is forgiven by the brother (or the relatives, etc.) of the killed against blood money, then adhering to it with fairness and payment of the blood money, to the heir should be made in fairness. This is an alleviation and a mercy from your Lord. So after this whoever transgresses the limits (i.e. kills the killer after taking the blood money), he shall have a painful torment. And there is (a saving of) life for you in Al-Qisas (the Law of Equality in punishment), O men of understanding, that you may become pious
[Surah Al-Baqarah. Aayaat 178-179]
Ash-Shaybaan [rahimahullaah] reported from Qataadah [rahimahullaah] who said, “Amongst the people of the pre-Islamic era, there were those who used to transgress and follow shaytaan. If a person had a great number of supporters and strength, and then a slave of theirs is murdered by a slave of another people, then out of wanting to show their superior strength, they would say, ‘We shall not kill (by way of revenge) except a free person amongst them’. And if a woman kills another woman from another tribe, they said, ‘We shall not kill (by way of revenge) except a man amongst them”. So, Allaah revealed this Aayah.
And regarding the statement: [وَلَكُمۡ فِى ٱلۡقِصَاصِ حَيَوٰةٌ۬ يَـٰٓأُوْلِى ٱلۡأَلۡبَـٰبِ لَعَلَّڪُمۡ تَتَّقُونَ – And there is (a saving of) life for you in Al-Qisas (the Law of Equality in punishment), O men of understanding, that you may become pious], Az-Zujaaj [rahmahullaah] said, “If a man knows that he will be killed if he murders someone, then he will refrain from murder, so by way of this both the lives of others and his are preserved. [Ref 1]
Imaam Ibnul Qayyim [rahimahullaah] said, “He refrains from killing someone else out of loving and giving precedence to his life, so in this is a preservation of his life and that of the one he wants to kill. Also when a man killed another man from a family and a tribe, the family or tribe of the victim would kill everyone they can find from the family, tribe and city district of the murderer, and in this there was overwhelming corruption and destruction; so Allaah legislated the law of equality in punishment so that none else is killed except the one who committed murder. Therefore, this preserved the lives of murderer’s relatives and the people of his city. [Ref 2]
Imaam As-Sadi [rahimahullaah] said, “By way of it [i.e. the law of equity in punishment] life is preserved and the misguided ones who exit the confines of justice are restrained. The one who knows that he will be killed if he kills, then he may not attempt to kill. And when others witness a murderer being executed [i.e. by the government], they will take heed and refrain from the crime of murder. So, if the punishment against a murderer was other than killing him [by way of capital punishment], the evil act of murder would not have been prevented. This is the case regarding all the prescribed punishments of the Sharee’ah, because they contain means of prevention of that which shows the perfect Wisdom of The All-Wise , the Oft-Forgiving.
And Allaah specified the mention of life in this Aayah as emphasis and exalting it. And when it is the case that none knows the reality of this ruling except the people of sound intellect and strong understanding, Allaah addressed them specifically. [Ref 3]
Sharī’ah Law and Crime
[Ref A: An Excerpt from ‘As-Sawaa’iq Al-Mursalah Alal Jahmiyyah Wal Mu’attilah’ – Vol 3. page 927. slightly paraphrased]
[Ref B: Excerpt from ‘Al-Haqeeqatus Shar’iyyah Fee Tafseeril Qur’aan Al-A’dheem Was-Sunnatin Nabawiyyah’ page 17. slightly paraphrased]
[Ref 1: An Excerpt from Zaadul Maseer Fee Ilmit Tafseer. By Imaam Ibnul Jawzi (rahimahullaah)]
[Ref 2: An Excerpt from Miftaah Daar As-Sa’aadah 431-432. Slightly paraphrased]
[Ref 3: An Excerpt from Tafseer as-Sadi. Slightly paraphrased]