This matter remains as to why Bid`ah is such a detestable deed. The seniors of the Deen have made many lengthy discussions on this subject. I will briefly state a few reasons, hereunder:
Firstly, the completion and perfection of the Deen of Islaam was made by Nabi (sallAllaahu alaihi wasallam). Nabi (sallAllaahu alaihi wasallam) had also outlined and expounded on all those actions and ways in which one can gain nearness, proximity and the Pleasure of Allaah Ta`ala. Now if any person innovates any action and calls people towards it, it will be as if he is implying that the Deen of Nabi (sallAllaahu alaihi wasallam) is, Nauthubillaah, incomplete and deficient. And that this means of gaining proximity to and acquiring the Pleasure of Allaah Ta`ala which was innovated by this idiot was, Nauthubillaah, unknown to Nabi (sallAllaahu alaihi wasallam). Or it also implies that the intricacies of the Deen was better understood by this Bid`ati than it was by Nabi (sallAllaahu alaihi wasallam), his Sahaabah and Tabieen, Nauthubillaah.
In short, if a person makes that action a part of Deen and regards it as an Ibaadat, which neither Nabi (sallAllaahu alaihi wasallam) nor the Sahaabah nor Tabieen carried out, is not merely making an assault on the way of the Salfe- Saaliheen, he is in fact, making an attack on the Deen which was brought by Nabi (sallAllaahu alaihi wasallam). Hence, what doubt can there be in this person being accursed and rejected? Secondly, besides Bid`ah, when a person carries out any other sinful action, he does discern that he is doing an incorrect action. He may feel ashamed of his sin and repent. Contrary to this, Bid`ah is such an evil and despicable act that instead of understanding it as being incorrect, the perpetrator deems it as being meritorious action. Shaitaan presents this act to the perpetrator in such an acceptable form that he will never realise its incorrectness. He will be deprived of repenting therefrom until his death. It is for this reason that great, great sinners eventually gain the guidance of repenting, whereas there is no cure from the disease of Bid`ah, except, if Allaah Ta`ala showers His Special Mercy on that person and he realises the error of his ways.
Thirdly, the evilness of Bid`ah deprives a person of the Noor of Sunnat. Nabi (sallAllaahu alaihi wasallam) said: “When any nation innovates a Bid`ah, then its equivalent Sunnat is lifted (removed) from them. Therefore, to adhere to even the smallest of Sunnats is by far better than innovating a Bid`ah.” [Ahmad, Mishkaat, page 31]
It is reported in another Hadith: “No nation innovates a Bid`ah except that Allaah Ta`ala removes from them a Sunnat equal to it, and it (the Sunnat) will never return to them until the Day of Qiyaamah.” [Mishkaat, page 31]
The reason for the removal and eradication of the Sunnat is that once a person practices upon a Bid`ah then the Noor and abilities of the heart are eliminated. A person is unable to differentiate between Haqq and Baatil. The example is like that of an inexperienced stupid person. He desires that his real money be increased. So, he is given a bag full of counterfeit money in exchange for his few genuine coins. This idiot is now happy with himself in that he feels that he has achieved an excellent bargain. However, his happiness will be short -lived. Once he reaches the market-place, not only will he realise the actual worth of his „money., he will also be accused of dealing in counterfeit money.
Understand well, on the day of Qiyaamah, only the currency of the Sunnat of Nabi (sallAllaahu alaihi wasallam) will be acceptable. Those who will take with them the counterfeit currency of the Aakhirah in the form of Bid`ah will realise its worthlessness. They will also be accused of bargaining away the genuine currency of the Sunnat of Nabi (sallAllaahu alaihi wasallam) for the worthless Bid`ah counterfeit. It is stated in a Hadith: “I will reach the Hawdh-e-Kauther before any of you. Whoever comes to me will drink of its water, and whoever drinks of its water once will never again feel thirsty. Some people will come towards me who I will recognise and they will recognise me, but there will be a barrier between us. I will say that these are my people, whereupon this reply will be given to me: „You do not know what these people did after your demise (i.e. what they had innovated into the Deen).. Upon hearing this reply, I will say: „Away with him, away with him who has changed the Deen after me..” [Agreed upon, Mishkaat, page 488]
From this narration it is quite evident that those who innovate in the Deen will be deprived of the water of Kauther on the day of Qiyaamah, by Nabi (sallAllaahu alaihi wasallam). What bigger deprivation than this can there be? It is for this reason that the pious predecessors have voiced such great dislike and hatred for Bid`ah. Imaam Ghazaali (rahmatullahi alaih), after explaining and encouraging the need for following the habitual traits of Nabi (sallAllaahu alaihi wasallam) states: “Whatever we have mentioned was in order to encourage the following of the habitual of traits (of Nabi – sallAllaahu alaihi wasallam). But, regarding those actions (of Nabi – sallAllaahu alaihi wasallam) which are connected with Ibaadat, the exclusion of any of these, without valid excuse, is nothing other than Kufr-e-Khafi (light kufr) and Himaaqat-e-Jali (clear and open stupidity).” [Tableegh-e-Deen Tarjuma Arbaeen, page 42]
Imaam Rabbaani Mujaddid Alfe Thaani rahmatullahi alaih) states: “This humble servant is imploring Allaah Ta`ala with utmost humility, pleading, beseeching and begging, secretly and openly, that He does not get my companions and I entrapped in any new innovation in the Deen which was not practiced by Nabi (sallAllaahu alaihi wasallam) and the Khulafaa-e-Raashideen (radhiAllaahu anhum), even though that newly innovated thing may appear to be as glittering as the sun. He should not allow us to be fascinated or impressed with its (outward) „beauty‟. (May He accept this supplication through the) mediation of the Best of all mankind sallAllaahu alaihi wasallam).” [Maktoob 186, part 1]
Fourthly, The abovementioned Hadith of Nabi (sallAllaahu alaihi wasallam): “Away with him, away with him who has changed the Deen after me.” Expounds one other aspect of the accursedness of Bid`ah, and that is this fact that Bid`ah necessitates the alteration and adulteration of the Deen.
Allaah Ta`ala had revealed this Deen (to last) until Qiyaamah. Every human, until the Day of Qiyaamah is bound to this Shariah. This compulsion will remain as long as the Deen is secured upon its original form. Just as the previous nations altered and changed their respective religions to suit their whims and fancies, thereby eradicating its original form, should not happen to this Deen.
Hence those people who innovate Bid`ahs into the Deen are in reality changing the face of the Deen, thereby opening the way for alteration and adulteration in the Deen. Nevertheless, since Allaah Ta`ala has given the undertaking of protecting this Deen, it is through His Mercy and Benevolence that He has made arrangements for its protection. The whims and fancies of people in every era had attempted to change the beautiful face of the Deen, but Allaah Ta`ala had created rightful Ulama in each of these eras to combat these innovations, thereby safeguarding the Deen.
Nabi (sallAllaahu alaihi wasallam) stated: “Every future generation, will have just and rightful people who will shoulder the knowledge, wherewith they will eradicate the changes of those who indulge in excesses in the Deen, of the falsities of the wrongdoers and of the false interpretations of the ignorant ones.” [Mishkaat, page 36]
Alhamdulillah, all Praises are due to Allaah Ta`ala that the Baatil of the people of Baatil will never be successful in changing the beautiful face of this Deen, because Allaah Ta`ala had himself formulated the system for its protection. However, it is a matter without doubt that these people who innovate new, new things into the Deen, not only make apparent their wickedness, they lead many ignorant people astray as well.