Definition of BID'AH SAYYIAH

Bid'ah say'iah is a new thing, introduced to and made part of the Deen (Islam) that has no origin what so ever from the Qur'an or the Sunnah of Rasoolallah [May Allah bless Him and grant Him peace]

Imam Bukhari and Imam Muslim write that there was some companions talking and the Prophet was listening. One of them said: 'I will make prayers (Salaah) all night long.' The second said: 'I will fast (sawm) all the time.' The third said: 'I will never marry.' When our Prophet [May Allah bless Him and grant Him peace]heard them say this he said: 'I am the most God conscious of Allah (Ta`ala) than any of you. I pray (Salaah,) I fast (sawm) as well, and I do marry woman too. And who so turns his face from my Sunnah, cannot be of my Ummah'.

[Mishkat Muslim, Bukhari chapter Ihtisam]

The reason why our Prophet [May Allah bless Him and grant Him peace]stopped them from doing what they wanted to do was because it was against Sunnah(his way). What ever we do which is against the way of our Prophets [May Allah bless Him and grant Him peace] Sunnah is a Bid'ah Say'iah.

RasoolAllah [May Allah bless Him and grant Him peace] stated: "On the Day of Judgement, some people will come to me when I will be standing by Haudh-e-Kauser (Well). They will be grabbed and taken towards the Hellfire. I shall say: "These are my people" but in reply I will be told: "These are the people who introduced innovations after you, so they are unbelievers."