The ruling of adding something to the Deen which is not legalized by Allah or the ProphetAllah, the Exalted, says: (Yes, but whoever submits himself to Allah and he is a Muhsin (good-doer) then his reward is with his Rubb (Allah) on such shall be no fear, nor shall they grieve.) (2:112)
This means the one who sincerely observes practices for the sake of Allah, and does them in accordance to the Sunnah of the Prophet…they alone are the ones who would enter Jannah (Heavenly Gardens).(Tayseer al-Kareem ar-Rahman fi Tafseer Kalam al-Man'naan for Sheik as-Sa'di, may Allah have mercy on him.)
Imam Ahmed, may Allah have mercy on him, narrated on the authority of Abdullah b. Masood, with whom Allah is pleased, that he said: 'The Prophet drew a line, and then said: "This is the Path of Allah" and then he drew small lines on the right and left of this line, and he said: "These are paths, upon each path there is a Shaitan calling people." He then recited the words of Allah: (And verily, this is My Straight Path, so follow it, and follow not (other) paths, for they will lead you from His Path. This He has ordained for you so that you may become Al-Muttaqun (the pious).) (Ibn Hib'ban #6) The Prophet also said: 'Indeed the most truthful of speech is the Book of Allah, and the best of guidance is the guidance of Muhammad and the most evil of matters are the innovated ones, and every (religious) innovation is a Bid'ah, and every Bid'ah is a means of deviation, and every deviation would lead to the Fire.' (Ibn Khuzaimah #1785)
Allah, the Exalted, also says: (And follow not that of which you have no knowledge. Indeed, the hearing, the sight and the heart - about all those [one] will be questioned.) (17:36)
Allah, the Exalted, also says: (Or have they partners with Allah (false gods) who have instituted for them a Deen which Allah has not allowed.) (42:21)
Whoever innovates a religious rite or practice in the Deen of Allah, while legalizing something illegal in Islam, or illegalizing something legal, he would become a disbeliever if he does not repent, as reported in the Hadeeth of the Prophet in which he explained the words of Allah: (They (Jews and Christians) took their rabbis and their monks to be their god besides Allah.) (9:31)
He said: 'Even though they did not worship them (openly) but they would deem lawful whatever their rabbis and monks made lawful, and deem unlawful whatever their rabbis and monks deemed unlawful.' (Tirmidthi #3095)
This stern warning encompasses those who follow them in proclaiming things as lawful or unlawful when they are not.
The scholar, Sheik Abdurrahmann as-Sa'di, may Allah have mercy on him, said: 'They (i.e. rabbis and monks) would legalize for their people laws and verbal statements which belie the Deen of the Messengers, and people would follow them. They would aggrandize their Sheiks, and pious people; such that they would take them as gods besides Allah; people would offer sacrificial animals, beseech and supplicate them.'
What is Bid'ah?
In order to understand the meaning of Bid'ah, we must know what Sunnah implies. Imam Ibn Rajab, may Allah have mercy on him, said: 'Sunnah is a followed path; it includes what the Prophet and his rightly-guided Caliphs adhered to from creedal beliefs, observance of practices, and sayings…this is the complete Sunnah.'Read More +
Religious Innovations can be categorized into three categories: Bid'ah which is tantamount to disbelief, which would take one out of the folds of Islam; such Bid'ah pertains to creedal issues, such as one who offers sacrificial animals to other than Allah, and one who circumambulates a grave, and one who beseeches and seeks help of other than Allah in matters that they ...Read More +
The Stance of Shari'ah regarding Religious Innovations
One should know that the second Testimony of Faith, 'Muhammad is the Messenger of Allah', requires the person to obey him, and believe in what he has informed us about and to stay away from that which he has forbidden. It also requires that a person worship Allah in the allowed and sanctioned manner, not in a way he desires or wishes. ...