1 --- Know that Islam is the Sunnah and the Sunnah is Islam and one can’t be established without the other.
The prophet sallalalhu alaihi wa sallam said: He who turns away from my sunnah is not from me. Sahih Bukhari.1/1-2/no.1), Muslim (eng. trans. 2/703/no.3236) and an-nasaee.
Abu Hurairah said that Allah's messenger sallalahu alaihi wa sallam said: "All of my ummah will enter paradise except those who refuse." It was said who will refuse? He replied whoever obeys me enters paradise and whoever disobeys me has refused. (reported by Bukhari and muslim 2/703/no.323 9/284/no.384)
imam az zuhri (the famous the tabi’ee, died in 124 hijra) said " The people of knowledge who came before us used to say salvation lies in clinging to the sunnah"
reported by Ad dharimi in his sunan. (no.96)
Imam Malik said: the sunan is like the Ark of Noah whoever embarks upon it reaches salvation and whoever refuses is it has drowned. Quoted by shaykhul islam ibn taymmiyah (4/57)
Point 2 --- From the Sunnah is clinging to the jamaah1 whoever desires other than the jammah in departs from it he has thrown off the yoke of islam from his neck and he is astray and leads others astray.2
1 jamaah --- Umar radiAllah anhu reports that the prophet sallahu alaihi wa salam said, "stick to the jamaa'ah and beware of splitting for shaitan is found along with the single person but is further from two. whoever desires the centre of Paradise then let him stick to the jamm'ah. He whose good deed pleases him and his evil deed causes him to feel bad then he is a believer"
reported by Ahmad ( 1/18), at-Tirmidhee (no.2165) and al-haakim (1/114) and is declared saheeh by shiekh al albani in as saheehah (no.1116)
Anas reports that the prophet said indeed the ppl of israel into 71 sects and my ummah will divide into 72 sects all of them in the fire except one and that is the jamaah. Ibn majah 3993 and declared sahih by Shaykh albani.
2 Alluding to the hadith of Ibn Abbas said the prophet said: "He who sees from his ruler something he dislikes, let him be patient with him, for he who splits away from the jammah by a hand span and then dies, dies a death of jahiliyah" and in a narration "then he has thrown off the yoke of Islam from his neck." Reported from al Bukhari 9/145 Muslim and Ahmad 4/130 and tirmidhi 2867.
Point 3-------The foundation of the jammah is upon the companions of the prophet they are ahl sunnah wal jamaah1 whoever does not take from them has gone astray and innovated And every innovation2 is misguidance and misguidance and its people are in the fire3.
1 ahl sunnah wal jammah as shown by hadeeth at tirmidhi hadteeth no 2641 Abdullah ibn amr said the messenger of Allah said what happened to the people of israel will happen with my ummah Just as one shoe resembles the other to the point that if one of them had relations with his mother openly there wud be someone who did that in my ummah. The children of israel split into 72 sect my ummah will split into 73 sects all of which are in the fire except one They asked which is that one o messenger of Allah He replied that which I and my companions are upon. Declared hasan by shaykh Albani.
2 It is authentically reported that Allahs messenger has said stick to my sunnah and the sunnah of the rightly guided caliphs after me, cling to it with your molar teeth because every innovation is misguidance. Reported by Ahmad Abu dawood 3/1294/no 4590 At tirmidhi no 2676 ibn majah 42 shaykh Albani declared it sahih and said the narrators are reliable.
3 Jabir reports that the prophet would say in his khutbah the best speech is the book of Allah the best way is the way of Muhammad the worst of affairs are the novelties and every novelty is an innovation and every innovation is misguidance and every misguidance is in the fire. Reported by an nasai 3.188 it is declared sahih by shaykh Albani in sahih sunan an nasai 1487.
Point 4----'Umar ibn al-khattab, (radhiAllahu 'anhoo) said, "There is no excuse for anyone going astray thinking that he is upon guidance. Nor for abandoning guidance thinking it to be misguidance, since the affairs have been made clear, the proof established1 and the excuse cut off."2 That is because the Sunnah and the Jamma'ah have consolidated and safeguarded all of the Religion. it has been made clear to the people, so it is upon the people to comply and follow.3
1 Al-‘Irbaad ibn Saariyah, (radhiAllahu ‘anhoo) reports that the Prophet (‘allayhees Salatu wassalam) said, “... I have left you upon clear guidance. Its night is like its day. No one deviates from it after me except that he is destroyed.” Reported by Ahmad, Ibn Maajah (no.43) and Al-Haakim. It is declared saheeh by Shaikh Al-Albani in as-Saheehah (no.937).
2 Reported by Ibn Battah in al-ibaantul-Kubraa (no.162) by way of al-Awzaa’ee that it reached him that ‘Umar ibn al-Khattab said it. However, its chain is munqati’ (disconnected).
Al-Marwazee reports in as-Sunnah (no.95) that ‘umar ibn ‘Abd al-‘Azeez said, “There is no excuse for anyone, after the Sunnah, to be misguided upon error which he thought was guidance.”
3 ‘Abdullah ibn Mas’ood, (radhiAllahu ‘anhoo), said: “Follow and do not innovate, for you have been given that which is sufficient and every innovation is misguidance.” Reported by Abu Khaithamah in Kitaab ul-‘ilm (no.540) and declared saheeh by Shaikh Al-Albani.
Point 5----May Allah have mercy upon you. Know that the religion is what came from Allah, the Blessed and Most High. It is Not something left for the intellect and opinions of men. Knowledge of it is what comes from Allah and His messenger ('allayhee salat wassalam), so do not follow anything based on your desires and to deviate away from the Religion and to leave islam. There will be no excuse for you since Allah's Messenger (allayhee salat wassalam) explained the Sunnah to his Ummah and made it clear to his companions and they are the Jaama'ah, and they are the Main Body (as -sawaad ul-A'dham), and the Main body is the truth and its followers1. So he who contradicts the Companions of Allah's Messenger ('allayhee salat wassalam) in any of the affairs of the Religion then he has fallen into disbelief.2
1 Imam Ahmad reports in his musnad (4/278) with hasan isnaad the narration of Nu’maan ibn Basheer: Abu Umaamah al-Baahilee, (radhiAllahu ‘anhoo) said, “stick to the main body (as-Sawaadul – a’dham), so a man said, “what is the ‘main body’? So Abu Umaamah said, “This Aayah (54) in Soorah An-Noor: “...but if you turn away, he (Messenger Muhammad ‘Allayhees Salat Wassalam) is only responsible for the duty placed on him (i.e. to convey Allâh's Message) and you for that placed on you...”
Ibn Mas’ood, (radhiAllahu ‘anhoo) said, “ The Jamaa’ah is what conforms to the truth, even if you are alone.” Reported by Ibn ‘Asaakir in Taareekh Dimashq with a saheeh isnaad as pointed out by Shaikh Al-Albani in al-Mishkaat (1/61).
2 Allah, the Most High, did not only warn against opposing His Messenger ('allayhee Salat Wassalam) but also warned against the following of any way other than that of the first Believers: the companions, radhiAllahu 'anhum, amongst whom the Qur`aan was sent down and who learned directly from the Messenger ('allayhee salat wassalam). Allah the Most High says:
And whoever contradicts and opposes the Messenger (Muhammad SAW) after the right path has been shown clearly to him, and follows other than the believers' way. We shall keep him in the path he has chosen, and burn him in Hell - what an evil destination. (An-Ni.sa 4:115).
So he who totally abandons their way and instead follows the way of the devils, like the extreme Raafidhees, Baatinees and the extreme Soofees who worship others besides Allah, then he has left the religion.