It is very important that a believer must follow the correct manhaj (methodology) in obeying Allah. It is possible that a number of personal interpretations can be derived from the Quran and Sunnah. This would lead to divisions and differences between the ummah which ultimately results in broken deen or religion. One of the prime reasons for the divisions and sects in Islam is because of the absense of true manhaj. Allah (swt) revaled the last and final message to the last and final messenger Prophet muhammad (Pbuh). Our beloved Prophet (Pbuh) was a personaification of Holy Quran and commands of Allah. He said “This Ummah will split into seventy three parties, all of which will go to Hell – except for one party: the one which will follow the same path as what I and my companions are following today.[Authentic; recorded by Abu Dawud, at-Tirmidthi, and others]
Allah has said (what means): Whoever contends with and contradicts the Messenger after guidance has been clearly conveyed to him, and follows a path other than that of the Faithful Believers, We shall leave him in the Path he has chosen and land him in Hell, what an evil destination![An Nisa 4:115]
Shaikh ul-lslam ibn Taymiyyah (rahimahullah) commented on this ayah: “All who contradict and oppose the Messenger (Pbuh), after the right path has been clearly shown to them, have followed other than the Path of the Believers. And all who follow other than the Path of the Believers have contradicted and opposed the Messenger (Pbuh). If one thinks that he is mistaken in following the Path of the Faithful Believers, he is in the same position as one who thinks that he is mistaken in following the Messenger (Pbuh).”
Prophet (Pbuh) said “The best of people is my generation, then those who come after them, then those who come after them[Bukhari and Muslim]
Therefore we understand that it is compulsory to follow the teachings of Islam and understand the teachings in the way in which first three generations understood it.
As-Salaf us-Salih (or briefly: the Salaf) refers to the first and best three generations of Muslims. They are the Companions (Sahabah) of the Prophet (S), their immediate followers (Tabiun), and the followers of the Tabi’in. The correct manhaj or methodology is that of which the Salaf (predecessors) of this ummah were upon, from the Sahaabah, the Tabi’een and those esteemed Imaams from correct ‘Aqeedah, sound Manhaj and true Eemaan as well as strictly adhering to Islaam based upon Aqeedah, the legislation, etiquettes and (good) manners.
TheSalaf us-Saalih are distinguished for their adherence to the methodological principles outlined in the Book of Allaah, the Sunnah of His Messenger and the practice of the Companions.
Thus, in the arena of Aqeedah (creed) the Salaf us-Saalih follow a particular methodology, which is opposed to that of other than them, such as the Ash’arees, the Mu’tazilah and their likes whose hallmark is to raise the intellect and kalaam (theological rhetoric) over the texts of the Book and the Sunnah and the well-known sayings of the Imaams of this ummah.
Similarly, in the arena of Ibaadah (worship), the Salaf us-Saalih adhere to a methodology opposed to that of the intoxicated Soofees and Grave worshippers, who invent and innovate into the religion that for which Allaah sent down no authority.
Similarly, in the arena of Da’wah (calling to Allaah) and current affairs, the Salaf us-Saalih are distinguished from the innovated and pretentious methodologies of the political activists, who under the guise of following the Salaf and the contemporary Ulamaa, rouse the emotions and sentiments of the common-folk, take them away from the firmly established scholars and merely call to themselves.
Therefore you should make sure that you follow the right manhaj or methodology; else our worship and deeds will not be accepted by Allah. The right manhaj or methodology is to understand Quran and Sunnah according to how Prophets companions and following two generations understood it.