A wazeefa is basically any kind of zikr that a person recites in large quantities. Some people are in the habit of doing wazeefas with absolutely no knowledge about the wazeefa. Then they end up with various physical problems and wonder why.
Different forms of zikr have different qualities. The most intense forms of zikr are known to be jalali. They require that a person is very religious so that his soul can take the weight of the zikr.Ask a body builder to lift extemely heavy weight and he will not have any problems in doing so, but ask a normal person and his back will break. Similar is the case with zikr. If a person who does not pray five times a day and indulges in sins sits down to do zikr in the form of a wazeefa, say thousands of times a day, he can end up with a number of problems, some very serious. This is because his soul will not be able to tolerate it.
I have noticed that people on the internet are sitting waiting to give permissions for doing wazeefa. Permission can only be taken from someone you know personally. There are also other conditions. A person must pray five times every day. He must abstain from sins. He must be pak. He must avoid certain kinds of halal food until he finishes the waeefa.
Zikr of Allah is pure and it will only attract pure. It repels the impure. That is why while doing a wazeefa a person must be pure in mind, heart, body and soul.
One thing must also be kept in mind. Even if a zikr is not jalali and a person does it in the form of a wazeefa, he will only be able to see the result and positive effect of the wazeefa if he prays five times a day and avoids sins.