The Prophet peace be and blessings upon him used to retreat into his mosque for private devotions during the last ten days of Ramadan, but during the last Ramadan of his life he had secluded himself for twenty days. (Al‐Bukhaari, Kitab ul‐A'itika)
The Qur’an used to be reviewed by the Prophet peace be and blessings upon him with Jibreel (Gabriel) once annually during Ramadan, but this
was done twice in the year which he died. The Prophet peace be and blessings upon him at such a time told his companions that he had some strong feelings that the time of his departure from the world was drawing near.
No man has ever had the glowing desire to meet the Lord as possessed by the Prophet peace be and blessings upon him, and Allah now gave
him permission to quit the fleeting world. The companions of the Prophet peace be and blessings upon him held him dear like the apple of one’s eye. His death was thus a shock more terrible than what they could be expected to endure. But Allah had in His infinite wisdom prepared them beforehand for that unprecedented heartache.
The rumor about the Prophetʹs death had been circulated around in
the battle of Uhud, but later on it came out that Allah had still not deprived them of the blessed companionship of His Prophet peace be and blessings upon him. Yet none of them had regarded the Prophet peace be and blessings upon him as immortal for they knew that he would have to leave this world sooner or later. It was on that occasion
that the revelation was sent down by Allah to forewarn Muslims. As the Qur'an says:
“Muhammed is but a messenger, messengers (the like of whom) have passed away before him. Will it be that when he dieth or is slain, ye will turn back on your heels? He who turneth back doth not hurt Allah, and Allah will reward the thankful.”
[Soorah Aali‐Imraan 144]
The earliest Muslims had been guided, trained and set right by the Prophet peace be and blessings upon him. Their hearts were harmonized with Allah and they were all put in harness at the great task of spreading the message of Islam to the farthest corners of the world. And they never had any doubt that the Prophet peace be and blessings upon him would one day be summoned by the Lord in order to be recompensed for the greatest service rendered by him in humanity.
“When Allah’s succor and the triumph cometh,” had convinced the companions that it was but the first announcement of the Prophetʹs approaching departure from their midst. They were fully conscious of
the fact that reference to the help and victory coming from Allah signified completion of the Prophetʹs (peace be and blessings upon him) mission.
Then, when the revelation came,
“This day have I perfected your religion…”, a number of eminent
companions of the Prophet peace be and blessings upon him were led to believe that the time for his final summons was drawing near.
(Ibn Kathir, Vol. IV, p. 427)