Sahih Al Bukhari Volume 1 Revelation. Hadith number 6.

Heraclius receives a letter from Prophet Muhammad (peace be upon him), inviting him to Islam.

Heraclius reads the letter, and the content of the letter urges him to accept Islam, assuring him safety and promising a doubled reward from Allah if he converts. It also warns of the consequences of rejecting the invitation.

Heraclius, after reading the letter, discusses the matter with his advisers and priests. There is a sense of anxiety and concern among them.

Heraclius recalls a dream or astrological sign he had seen, indicating the rise of a leader associated with circumcision (a practice common among Muslims). He becomes worried and contemplates the implications.

A messenger from the king of Ghassan arrives and informs Heraclius about Prophet Muhammad's message. Heraclius inquires about the messenger's circumcision, confirming the connection with the Arabs.

Heraclius realizes the significance of the events, believes in the emergence of Prophet Muhammad as a leader, and sends a letter to his friend in Rome sharing his thoughts.

Heraclius gathers the Byzantine leaders in Homs, tests their conviction by suggesting they embrace Islam, and witnesses their negative reaction.

Heraclius then reveals that his earlier statement was a test of their faith. The people acknowledge their resistance to Islam, and the episode concludes.

This Hadith reflects the historical context of the early interactions between the Byzantine Empire and the nascent Muslim community, illustrating how leaders of that time perceived the rise of Islam and Prophet Muhammad (peace be upon him). It also underscores the political and religious implications of accepting or rejecting the message of Islam during that period.