Lawyers should fear Allah and help their clients get out of their dilemmas using lawful means. It is impermissible for a lawyer to resort to unlawful means to rescue a guilty client.
Sheikh Muhammad Al-Mubarak, professor at Imam Muhammad Ibn Saud University, Saudi Arabia, states the following: Being a lawyer is a permissible profession. It is a kind of legal authorization. However, it should not include any oppression or confirmation of anything unlawful.
A lawyer may not defend someone if he is not convinced of that person’s innocence. He may not assist someone in taking what is someone else’s right by way of embellished or false speech.
In the case where a lawyer knows that his client is not innocent or not in the right, but he uses evidence to defeat the other party and convince the judge of a falsehood, then the lawyer is engaged in something unlawful, whether that lawyer is motivated by money or by some other purposes.
The ruling that the judge gives does not make lawful in actuality something that is truly unlawful. The judge only gives his ruling according to what he hears from the two parties. Allah knows what is concealed in the hearts of both parties and He will judge between them on the Day of Judgment. The guilt in this instance will be upon all those who wilfully participate in the wrongdoing, meaning the lawyers and their guilty clients.
The Prophet (peace and blessings be upon him) is reported to have said, “You come to me with your disputes and perhaps some of you present your cases more eloquently than others. So, if I give a judgment in his favour because of his testimony and because of it he takes what rightfully belongs to his brother, then I am merely giving to him a piece of the Hellfire, so he should not take it.” (Al-Bukhari and Muslim)