On the cause with an example.

The Shaykh : If a person restricts an absolute act of worship with a specific cause, we say this is a religious innovation (bid'ah), unless the Shari'ah has come down stating that this cause is a cause for it. Do you understand? That is to say, if there is an absolute act of worship that is not restricted by a cause, and a person comes and restricts it with a specific cause, we say this is a religious innovation (bid'ah). So if he says, "This is an act of dhikr," we say, "Fine, it is absolute dhikr, and you have made it dhikr restricted by a cause for which the Shari'ah has not come down." A good example of this is if a person designates the night of the birth of the Prophet (peace and blessings be upon him) for a specific dhikr, whether it is dhikr of Allah or dhikr of the Messenger of Allah (peace and blessings be upon him) by praising him, eulogizing him, and sending blessings upon him. We would say this is a religious innovation (bid'ah). If he says, "How do you declare it an innovation when one remembers Allah or praises the Messenger (peace and blessings be upon him) with the praise he deserves, without exaggeration?" We say, "We do not deny dhikr, nor do we deny praising the Messenger (peace and blessings be upon him). In fact, we see that it is obligatory for us to give the Prophet (peace and blessings be upon him) his right of the praise and eulogy he deserves, without exaggeration or negligence. But we deny making it restricted by this cause, because this cause passed by the Prophet (peace and blessings be upon him) and passed by the Companions. Did they legislate this act of worship in it? No. Therefore, it is a religious innovation (bid'ah) from this angle, meaning from the fact that we restricted it with a cause for which the Shari'ah has not come down. Fine.