Short answer
The Quran is the word of Allah, revealed word for word and recited in worship. The Sunnah is the way of the Prophet ﷺ: his words, actions and approvals. A hadith is a report that records part of the Sunnah, with a chain of narrators. The Sunnah is not one book; it is gathered in hadith collections such as Bukhari and Muslim.
The Quran and the Sunnah are the first two sources of law, followed by consensus (ijma) and analogy (qiyas). Obeying the Prophet ﷺ is obeying Allah, so rejecting the Sunnah as a whole is not compatible with Islam.
The four schools agree on this.
Explanation
- The Quran: Allah's own speech, in Arabic, brought by Jibril, preserved letter for letter by mass transmission. It is recited in salah, and touching the mushaf needs wudu.
- The Sunnah: the Prophet's ﷺ way of life: what he said, what he did, and what he saw and approved. It explains the Quran: the Quran says to pray, and the Sunnah shows how.
- Hadith: a single report of the Sunnah, made of a chain of narrators (isnad) and the text (matn). Hadith are graded sahih (authentic), hasan (good) or da'if (weak).
- Hadith qudsi: words of Allah reported by the Prophet in his own wording; they are not part of the Quran.
The Quran itself tells you to take the Sunnah: "whatever the Messenger has given you, take" (59:7) and "he who obeys the Messenger has obeyed Allah" (4:80). Allah sent the Quran so that the Prophet ﷺ would explain it to people (16:44). He also said he was given the Quran and something like it along with it.
Is the Sunnah a book? No. It was preserved by the Companions in memory, practice and writing, then gathered by scholars into collections. The best known are the six books: Sahih al-Bukhari, Sahih Muslim, and the Sunan of Abu Dawud, al-Tirmidhi, al-Nasa'i and Ibn Majah, along with the Muwatta of Imam Malik and the Musnad of Imam Ahmad. AmalKit's Q&A cites these with sunnah.com numbering.
The four schools agree on all of this; they differ only in how they weigh certain kinds of hadith. See Sunnah, What is the Quran? and what is sharia.
The evidence
Quran, Surah Al-Hashr 59:7
مَّآ أَفَآءَ ٱللَّهُ عَلَىٰ رَسُولِهِۦ مِنْ أَهْلِ ٱلْقُرَىٰ فَلِلَّهِ وَلِلرَّسُولِ وَلِذِى ٱلْقُرْبَىٰ وَٱلْيَتَٰمَىٰ وَٱلْمَسَٰكِينِ وَٱبْنِ ٱلسَّبِيلِ كَىْ لَا يَكُونَ دُولَةًۢ بَيْنَ ٱلْأَغْنِيَآءِ مِنكُمْ ۚ وَمَآ ءَاتَىٰكُمُ ٱلرَّسُولُ فَخُذُوهُ وَمَا نَهَىٰكُمْ عَنْهُ فَٱنتَهُوا۟ ۚ وَٱتَّقُوا۟ ٱللَّهَ ۖ إِنَّ ٱللَّهَ شَدِيدُ ٱلْعِقَابِ ﴿٧﴾
And what Allah restored to His Messenger from the people of the towns - it is for Allah and for the Messenger and for [his] near relatives and orphans and the [stranded] traveler - so that it will not be a perpetual distribution among the rich from among you. And whatever the Messenger has given you - take; and what he has forbidden you - refrain from. And fear Allah; indeed, Allah is severe in penalty.
Muslims are commanded to follow what the Prophet brought.
Quran, Surah An-Nisaa 4:80
مَّن يُطِعِ ٱلرَّسُولَ فَقَدْ أَطَاعَ ٱللَّهَ ۖ وَمَن تَوَلَّىٰ فَمَآ أَرْسَلْنَٰكَ عَلَيْهِمْ حَفِيظًۭا ﴿٨٠﴾
He who obeys the Messenger has obeyed Allah; but those who turn away - We have not sent you over them as a guardian.
Obeying the Sunnah is obeying Allah.
Quran, Surah An-Nahl 16:44
بِٱلْبَيِّنَٰتِ وَٱلزُّبُرِ ۗ وَأَنزَلْنَآ إِلَيْكَ ٱلذِّكْرَ لِتُبَيِّنَ لِلنَّاسِ مَا نُزِّلَ إِلَيْهِمْ وَلَعَلَّهُمْ يَتَفَكَّرُونَ ﴿٤٤﴾
[We sent them] with clear proofs and written ordinances. And We revealed to you the message that you may make clear to the people what was sent down to them and that they might give thought.
The Prophet's role is to explain the Quran, which is what the Sunnah does.
Sunan Abi Dawud 4604
Grading to be checked... ألا إني أوتيت الكتاب ومثله معه ...
"Indeed, I have been given the Book and something like it along with it."
The Sunnah is revelation alongside the Quran.
Where the ruling is recorded
- Usul al-Shashi, Sections on the Book and the Sunnah. Hanafi usul text on the sources of law and their ranks.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.