The Hadith is the collection of sayings, actions, and approvals of the Prophet Muhammad, as transmitted by his companions.

The Sunnah is the primary source of the Hadith, which consists of the sayings, actions, and approvals of the Prophet Muhammad.

The Sira is the second most important source of the Hadith, which consists of the biography of the Prophet Muhammad.

The Ijma is the third most important source of the Hadith, which consists of the consensus of the Muslim community on a particular issue.

The Qiyas is the fourth most important source of the Hadith, which consists of analogical reasoning based on the Quran, the Sunnah, and the Ijma.

Sahih al-Bukhari is considered to be the most authentic collection of Hadith, compiled by Imam Bukhari.

Sahih Muslim is considered to be the second most authentic collection of Hadith, compiled by Imam Muslim.

Sunan Abu Dawud is considered to be one of the six major collections of Hadith, compiled by Imam Abu Dawud.

Jami` at-Tirmidhi is considered to be one of the six major collections of Hadith, compiled by Imam Tirmidhi.

Sunan Ibn Majah is considered to be one of the six major collections of Hadith, compiled by Imam Ibn Majah.

Muwatta Malik is considered to be one of the earliest collections of Hadith, compiled by Imam Malik.

Musnad Ahmad ibn Hanbal is considered to be one of the largest collections of Hadith, compiled by Imam Ahmad ibn Hanbal.

Sunan al-Nasa'i is considered to be one of the six major collections of Hadith, compiled by Imam al-Nasa'i.

Sunan al-Bayhaqi is considered to be one of the major collections of Hadith, compiled by Imam al-Bayhaqi.

Mu'jam al-Tabarani is considered to be one of the major collections of Hadith, compiled by Imam al-Tabarani.