In our society, a person who is supposed to be under the influence of magic is taken to so called ‘āmil's who recite certain words and then discover whether the person is really a victim of black magic or not. Please note that I am not talking about hysteria patients. I am also not talking about witch doctors when I use the word ‘āmil's. These ‘āmil's are pious people who have spent their lives in finding the effects of various Qur’ānic verses. My questions are:
1. How do we come to know that a person is a victim of black magic?
2. Should we consult ‘āmil's?
3. Do verses have mystical effects? A common example is the recitation of ‘Ayah-i-Karīmah to ask Allah to rescue one out of a bad patch in life?
As far as magic is concerned, one cannot deny its existence. The Qur’ān specifically mentions it as an evil discipline (siflī `ilm) practiced by the devils from both among the men and the jinn-folk:
And they followed what the devils used to enchant in the reign of Solomon; Solomon did not commit kufr but these devils did: they used to teach magic to people and they followed such things as were revealed at Babylon to the angels Hārūt and Mārūt. But neither of these taught anyone [such things] without saying: We are only for trial; so do not commit kufr. These people used to learn from them that which could sow discord between a man and his wife whereas these things cannot harm anyone without Allah’s permission. (2:102)
As specified by this verse, this magic is actually kufr (denial of faith), and therefore people should keep away from it. The question arises as to how should a person secure himself from becoming a victim to it. The answer is that, as a principle, in all things which can harm a person and which by nature are scientifically or medically explicable, help should be sought from the appropriate quarters. For example, if a person has an ulcer he should consult a gastroenterologist and if he has a bone fracture he should be shown to a specialist of orthopaedics. But if a person feels that he is the victim of some ailment which is not scientifically explicable, then the Qur’ān teaches him to put all his trust in Allah and pray to Him. The most appropriate thing to do in such cases is to recite the last two sūrahs of the Qur’ān and spend as much time as possible in remembering the Almighty. For, as the Qur’ān says in (2:102) nothing can harm a person unless it is the will of the Almighty.
In contrast to magic, which is kufr as declared by the Qur’ān, there seems to be another discipline (`ilm) which was revealed to the angels Hārūt and Mārūt; this was something of a defence against black magic so in vogue in the times of the Prophet Solomon (sws) in Babylon. Though it was not at all an evil `ilm, yet it was called a fitnah (test) which could be used the wrong way as well. This particular `ilm may be the one which lies with some of the ‘āmils of today; but then, nothing can be said with certainty.
Now these `āmil's are generally of two types in our society. The first category which constitutes almost 95% of them are those who generally fool the innocent masses by their buffoonery and by dramatic displays of wordplay. People end up losing lots of money and valuable time while getting "cured" from these fraudulent elements and sometimes pay the heaviest of prices for this -- they lose their relationship with Allah and become superstitious. To the second category belong those `āmil's which are actually psychologists, who handle patients purely through psychotherapy by suggesting them various mental and physical exercises. However, they too are not entirely free from practices such as wazā’if (incantations) which seem to have no basis in our religion. For example they will recite a verse of the Qur’ān and contend that it creates such and such effect on the person who recites it. This is something which finds no mention in the Qur’ān. Nowhere does Qur’ān specify that words or verses have mystical effects. Therefore, they should not be used for this purpose.
Consequently, my opinion in this regard is that one should stay away from these `āmil's as far as possible and spend one's time in remembering the Almighty and in seeking His protection by reciting the last two sūrahs of the Qur’ān. Also, there are many supplications (ad`iyah) mentioned various Ahādīth which serve the same purpose and can be recited.
The answer to your last question is that whenever a person is in difficulty, he should ask for Allah’s help in the very manner that has been prescribed in his Book. The Qur’ān says:
Seek Allah’s help through perseverance and prayer. (2:45)
All other ways lead us astray.