Is Being a Defence Lawyer Prohibited in Islam?
Question

When working as a defence lawyer, one may have to support and defend evil, because the defence lawyer tries to prove the innocence of the guilty person whom he is defending. Is the income of a defence lawyer who does that prohibited? Are there any Islamic conditions attached to a person working as a defence lawyer?
Praise be to Allah.Defence means protection, and if a person defends and protects evil then undoubtedly this is prohibited, because it means that he is falling into that which Allah has forbidden:
{but do not help one another in sin and transgression.} [Al-Ma’idah 5:2 – interpretation of the meaning]
But if he protects and defends good, then this is a praiseworthy kind of protection as enjoined in the verse:
{Help you one another in Al-Birr and At-Taqwa (virtue, righteousness and piety.)} [Al-Ma’idah 5:2 – interpretation of the meaning]
On this basis, whoever has prepared himself to do that must, before taking on a specific case, examine and study it.
If the one who is asking for his defence is in the right, then he should take on the case and support the truth and the one who is in the right; if the one who is asking for his defence is not in the right then he may also indulge in a case of that nature but the lawyer may go against the wishes of the one who is seeking his defence in the sense that he is protecting this person to prevent him from falling into anything that Allah has forbidden, and he does not defend him in the way that he wants.
That is because the Prophet (peace and blessings of Allah be upon him) said: “Help your brother whether he is a wrongdoer or one to whom wrong is done.” They said, “O Messenger of Allah, (we know what it means to help) the one to whom wrong is done, but how can we help him if he is a wrongdoer?” He said, “Stop him from doing wrong to others, that is how you will help him.”
If he knows that the one who is seeking his protection has no rights, then he must advise him and warn him and put him off getting involved in this case; he should explain to him what is wrong with his claim so that he will give it up out of conviction.
For more details, please see the following answers: 268937, 42521, 42523, 147668.
And Allah knows best.