The primary sources of the religion of Islam is the Quran, Hadith (Sunnah), Ijma (Consensus) and Qiyaas (Analogy) in that order. Qur’an and Hadith are where the majority of the teachings come from. When looking for guidance, a Muslim can also refer to one of these in order to educate themselves on a topic.
The Quran is the central religious text of Islam. It represents the fountainhead of Divine guidance for every Muslim. The Islamic sacred book is the words of Allah and was dictated to Muhammad (SAW), the prophet of Islam, by the Archangel Gabriel and was written down in Arabic. The chapters in this book touch upon all aspects of human existence, including matters of doctrine, social organization, and legislation. The Qur’an confirms the revelations given to earlier Prophets, though these might not be accessible to us, in the form they were originally revealed. The most sublime language and a rational message that directly appeals to the human heart have caused this Divine book to move nations and civilizations. It will continue to guide those who turn to Allah with a sincere heart, for all times.
Hadith’s are a collection of traditions containing sayings/actions of the Prophet Muhammad (SAW) that, with accounts of his daily practice (the Sunnah), constitute the major source of guidance for Muslims apart from the Quran. During the first few decades after the Prophet Muhammad’s passing, those who directly knew him (known as the Sahabah (Companions) shared and collected quotations and stories related to the Prophet’s (SAW) life.
Within the first two centuries after the Prophet’s passing, scholars conducted a thorough review of the stories, tracing the origins of each quotation along with the chain of narrators through whom the quotation was passed. Those which were not verifiable were deemed “weak” or even “fabricated,” while others were deemed “authentic” (sahih) and collected into volumes.
The most authentic collections of hadith include Sahih Bukhari, Sahih Muslim, Sunan Abu Dawud and Mishkat amongst others.
Here is an example of the difference between guidance from the Quran, and guidance from Hadiths:
In the Quran, there will be a verse from God that will state, “All Muslims must offer Prayer.” The Hadith will elaborate the amount, times and methods. The hadiths give us a in-depth process for every step of the prayer from start to finish. Whereas in the Quran we were only commanded to do the prayers.