Answer
Asalam Alaikum Abdallah,
Thank you for contacting About Islam with your question.
We may start with defining the terms we use here.
What is the Quran?
The Quran is believed by Muslims to be the actual word of Allah (the One True God) revealed to Prophet Muhammad (peace be upon him-PBUH) through Angel Gabriel. The meaning as well as the wording of Quran is from Allah. It contains many miracles. Linguistically, the Quran is miraculous in terms of wording and structure. Syntactically, and even scientifically, the Quran is also miraculous.
What is the Sunnah?
The Sunnah, or tradition, of Prophet Muhammad (PBUH) refers to all the sayings, actions, approvals, physical, and moral attributes of Prophet Muhammad. The Sunnah, Muslims believe, also has a miraculous nature, but is not the same as the Quran. While the meaning of the Sunnah is from Allah, the wording is from the Prophet.
The Relation Between the Quran and the Sunnah
Allah Almighty says in the Quran:
{[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.} (An-Nahl 16:44)
Commenting on this verse, Imam Al-Baghawi, one of the well-versed scholars of Islam, said in his tafseer:
The message — in the verse — refers to the divine inspiration. And the Prophet is the clarifier of the divine inspiration. The explanation of the Quran is to be sought in the Sunnah. (Al-Baghawi 25)
Thus the relation between the Quran and the Sunnah is such that the latter is a clarification of the former. The Sunnah explains and interprets the Quran. It gives more details about what is concisely mentioned in the Quran, especially when it comes to legal rulings.
Many laws, as well as acts of worships, are briefly mentioned in the Quran. Then, the Sunnah elaborates on such items and gives more details and explanation or interpretation.
A good example for this is the prayers. The Quran orders Muslims to pray, but it does not mention how many times Muslims should pray, or when and how to pray. But it does mention:
{And obey Allah and obey the messenger; but if you turn away, then upon Our messenger is only [the duty of] clear notification.} (At-Taghabun 64:12)
It also mentions:
{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.} (Al-Hashr 59:7)
So, Allah Almighty clearly orders us to follow and obey the messenger and take whatever he gives us. And as we are talking about prayers, the Prophet (PBUH) says:
Pray as you saw me praying. (Al-Bukhari)
The same applies to hajj (pilgrimage to Makkah), zakah (obligatory alms), fasting the month of Ramadan, monetary transactions, and so on. All of these are touched on briefly by the Quran, but the Sunnah elaborates on them.
It is worth mentioning that Quran is communally transmitted from generation to generation in such a way that a huge number of people memorized and transmitted it to the subsequent generation all the way from the time of the Prophet (PBUH) until today.
This is what makes the Quran so authentic, because it is impossible for an entire generation to be mistaken in their narration.
On the other hand, not all the Sunnah was transmitted to us in the same way as the Quran, only some of it is. However, Muslim scholars developed a very scientific and sophisticated methodology to categorize the narrations that come to us from the Prophet (PBUH).
This science is called hadith methodology. Using certain scientific criteria they can tell which narration is authentic and which is not.
In a nutshell, the Quran is inspired by Allah in meaning and wording. However, the Sunnah is inspired by Allah in meaning while the wording is from Prophet Muhammad (PBUH). Allah says in the Quran:
{Nor does he speak from [his own] inclination. It is not but a revelation revealed.} (An-Najm 53:3-4)
So, the Sunnah, as the Prophetic text, comes right after the Quran as part of the revelation, and both of them are the two main sources of Islam. Allah made it clear that the Sunnah should be followed when he says:
{He who obeys the Messenger has obeyed Allah.} (An-Nisaa’ 4:80)
A hadith that shows that Quran and Sunnah are interrelated, and warns against taking the Quran and abandoning Sunnah states:
Indeed I have been given the Book (that is, the Quran) and something like it along with it. (Abu Dawud)
To conclude, the Quran and the Sunnah together are the sources of guidance and laws for Muslims. The Sunnah is the explanation and interpretation of the Quran.
That is why they cannot be separated, as they work harmoniously to convey the message of Islam and show people what Allah wants from them in order for them to lead the best life on this earth and also to win Heaven in the hereafter.
I hope this answers your question. Please, keep in touch.
Walaikum Asalam.
Please continue feeding your curiosity, and find more info in the following links:
Difference Between Prophetic Traditions and Prophet’s Biography?