The first revelation is contained in Suratul 'Alaq. This Surah is the 96th chapter of the Quran, and it contains 19 verses. The first five verses of Suratul 'Alaq were the first revelation that was sent down to Prophet Muhammad (S.A.W.) by the Angel Jibril (A.S.) while he was in a cave on Mount Hira.
In this Surah, Allah commands Prophet Muhammad (S.A.W.) to recite in the name of his Lord. The Surah also describes the creation of humans and how they are taught knowledge by Allah. It emphasizes the importance of seeking knowledge and the consequences of rejecting it.
Suratul 'Alaq is also known as the Surah of Power because it speaks of the power of Allah and how it is manifested in His creation. The Surah also highlights the importance of prayer and seeking refuge in Allah from evil.
In conclusion, the first revelation is contained in Suratul 'Alaq, which is the 96th chapter of the Quran. This Surah contains the first five verses that were revealed to Prophet Muhammad (S.A.W.) by the Angel Jibril (A.S.) and emphasizes the importance of seeking knowledge and the power of Allah.