An action is not accepted by Allaah the Blessed and the Exalted, except if it contains two conditions:
Firstly: It should be done purely for the Face of Allaah the Mighty and Majestic.
Secondly: It should be righteous and it cannot be righteous, except if it is established from the sunnah, without opposing it. It has been confirmed by the researchers from the people of knowledge that every alleged act of worship that the Prophet (sallallaahu ‘alayhi wa sallam) did not legislate by his statement, or which he did not perform in order to get closer to Allaah – is in opposition to the sunnah. So the sunnah consists of two parts, sunnatul fi’iliyyah (the sunnah of actions) and sunnatut tarkiyyah (the sunnah of abandonment). So whatever the Prophet (sallallaahu ‘alayhi wa sallam) left off from acts of worship, then it is a sunnah to leave them off. Do you not see the likes of this in the adhaan (call to prayer) for the two ‘eeds, and in burying the dead, even though a person may be engaged in the remembrance and glorification of Allaah the Mighty and Majestic. It is not permissible to draw near to Allaah by that.
Indeed the Companions understood of the Prophet (sallallaahu ‘alayhi wa sallam) understood this meaning, so they issued general warnings against innovations such as what is mentioned regarding this topic from Hudthayfah (radiyallaahu ‘anhu). He said: “Every act of worship that the Companions of the Messenger of Allaah did not perform, then do not perform it.” ‘Abdullaah Ibn Mas’ood (radiyallaahu ‘anhu) said: “Follow and do not invent, for indeed you have been sufficed. Stick to the old matters. 
So whoever has his worship established from Allaah upon conformity to the sunnah of His Prophet (sallallaahu ‘alayhi wa sallam), and does not let it become mixed in with innovation, then let him rejoice in Allaah’s acceptance of his obedience. Allaah will surely place him in Paradise. May Allaah make us from those who hear the statement, and then obey in goodness.
Know that the innovation that you shall encounter is of two types:
Innovations which were extrapolated from a text, and their novelty is mentioned in the books of the people of knowledge, and this is a sign that it is traced back to them, and this type is abundant.
The other type is innovations that are not found in any text, rather the knowledge based principles and foundations judge them to be innovations. So this is proof that they are void in origin.
So these innovations emanate from the following matters:
Firstly: Weak hadeeths. It is not permissible to use them as evidences, or to attribute them to the Prophet (sallallaahu ‘alayhi wa sallam). According to what I have explained in the introduction to ‘Sifatus Salaatin Nabee‘, the likes of this is not a permissible action with us, and this was the methodology of a group of the people of knowledge such as Ibn Taymiyyah.
Secondly: Fabricated hadeeths, or those which there is no basis for. Their matter is well known to some of the fuqahaa` (legal jurists), yet they still base their rulings upon them. These are from the very essence of innovations and newly invented matters!
Thirdly: Reasoning, and approvals (istihsaanaat) made by some of the legal jurists – especially the later ones from amongst them – not supported by any legislative proofs. Rather they are carried on as accepted matters of the Muslims, until they are made sunnahs to be followed! It is not hidden from one who has insight into his Religion, that this is not permissible to be followed, since nothing can be legislated except for that which is legislated by Allaah. So if an action is acceptable according to the approver – if he is a mujtahid – then Allaah will not punish him for it. As for the people who take that as legislation, or a sunnah, then no. So how can that be when some of these actions oppose the sunnah-related actions, as will follow if Allaah the Exalted wishes.
Fourthly: Customs or superstitions which are not from the Revelation, and are not testified to by the intellect, even though some of the ignorant people may act upon them, and take them as revelation. These cannot be supported by their authorities, even if some of them are from the callers to knowledge, or from those who have their appearance.
Then you should know that the danger of these innovations is not only in one matter, rather it is upon levels. Some of them are clear shirk (associating partners with Allaah) and disbelief, as you shall see, and some of them are less than that. However, it is obligatory upon us to know that the smallest innovation a man brings into the Religion is prohibited after its matter is clarified. So innovations are not – as some people think – at the level of dislike (makrooh) only. How can that be when the Messenger of Allaah (sallallaahu ‘alayhi wa sallam) has said: “Every innovation is a misguidance, and every misguidance is in the Fire.”?  That means, the one who does it is in the Fire.
Indeed Imaam ash-Shaatibee has confirmed this with the best of explanations in his book, ‘al-I’itisaam‘. Due to this, the matter of innovation is a great danger. Most of the people are ignorant about it, except for a group from the people of knowledge. So enough for you as a proof regarding the danger of innovation is the statement of the Messenger of Allaah: “Verily Allaah veils the repentance of every person of innovation, until he leaves his innovation.” This is related by Tabaraanee, and by Diyaa`ul Maqdisee in ‘al-Ahaadeethul Mukhtaarah‘, and other than them with an authentic chain of narrators, and al-Mundthiree declared it good. (hasan) 
So I finish with these great words of advice to the reader from a great scholar from the early scholars of the Muslims. He was Shaykh Hasan Ibn ‘Alee al-Barbahaaree, from the companions of the companions of Imaam Ahmad, he died in the year 329H. He said:
“So beware of small innovations, because they grow until they are large. Such was the case with every innovation invented into this Ummah. At first it was small, resembling the truth, so some were deceived by that and entered into it. Then it was not possible for them to leave from it, so it grew, and the Religion was split into religions due to it. So look – may Allaah have mercy upon you – into the statements of everyone you hear from, in you age particularly. So do not rush into, or enter into anything until you ask and see: ‘Did anyone from the Companions of the Messenger of Allaah (sallallaahu ‘alayhi wa sallam), or anyone from amongst the scholars talk about it?’ So if you find a narration from them, then hold fast to it. Do not exceed it by anything, and do not give anything precedence over it, so as to fall into the Fire.
So know – may Allaah have mercy upon you – that a servants Islaam is not complete until he becomes and obedient, truthful Muslim. So whoever alleges that something remains from the matter of Islaam, not completed by the Companions of the Messenger of Allaah (sallallaahu ‘alayhi wa sallam), then he has indeed lied upon them, and has caused a schism by doing this, and he has lied upon them. So he is an innovator, misguided and misguiding, innovating into Islaam what is not in it. 
May Allaah have mercy upon Imaam Maalik since he said:
“The latter part of this ummah will not be rectified, except by that which rectified its first part. So whatever was not part of the Religion in those days, cannot be part of the Religion today. 
May Allaah have mercy upon our Prophet (sallallaahu ‘alayhi wa sallam) who said:
“I have not left anything that will bring you close to Allaah, except that I have commanded you with it, and I have not left anything that will distance you from Allaah and bring you close to the Fire, except that I have forbidden you from it. 
The Praise is due to Allaah, by whose favour righteous actions are perfected.
 This is a translation of (p. 100-105) of the book, ‘Hujjatun Nabee‘ by shaykh Muhammad Naasirud Deen al-Albaanee.
 Translators Note: Reported authentically in ad-Daarimee (no.211) at-Tabaraanee in al-Kabeer (no. 8870), al-Bayhaqee (no. 204), Ibn Wadaah in Bid’ah wan-Nahee ‘Anhaa p. 10, and also from Qataadah on p.11. Also related by Abee Khaythamah in al-‘Ilm (no. 54). Shaykh al-Albaanee has authenticated the narration in Bid’ah wan-Nahee ‘Anhaa.
 Translators Note: See: Saheeh Muslim (3/11), Ahmad (3/381), Nisaa`ee (1/234), al-Bayhaqee (3/214). A full checking of this hadeeth can be found in the book, ‘Khutbatul Haajah‘ by shaykh Muhammad Naasirud Deen al-Albaanee.
 Translators Note: See Silsilatul Ahaadeethus Saheehah (no. 1620).
 Related in Tabaqaatul Hanaabilah (2/18-19), of Ibn Abee Ya’alaa.
 Translators Note: Related in ash-Shifaa` of Qaadee `Iyyaadh, (2/676).
 Translators Note: Related in the Sunan of Imaam ash-Shaafi’ee (1/14), and by al-Bayhaqee (7/76), and by al-Khateeb in al-Faqeeh wal-Mutafaqqih (1/93). See shaykh Saleem al-Hilaalee’s introduction to his checking on Hidaayatus Sultaan for a proper checking of this hadeeth.