The companions concern over prophet (Peace be upon him) death.

The great (loss) news was soon known by everybody in Madinah. Dark grief spread on all areas and horizons of Madinah. Anas said:“I have never witnessed a day better or brighter than that day on which the Messenger of Allâh(Peace be upon him) came to us; and I have never witnessed a more awful or darker day than that one on which the Messenger of Allâh (Peace be upon him) died on.” When he died, Fatimah said: “O Father, whom his Lord responded to his supplication! O Father, whose abode is Paradise. O Father, whom I announce his death to Gabriel.”

Umar's (RA) attitude

‘Umar, who was so stunned that he almost lost consciousness and stood before people addressing them: “Some of the hypocrites claim that the Messenger of Allâh (Peace be upon him) died. The Messenger of Allâh (Peace be upon him) did not die, but went to his Lord in the same way as Moses bin‘Imran did. He stayed away for forty nights, but finally came back though they said he had been dead. By Allâh, the Messenger of Allâh (Peace be upon him) will come back and he will cut off the hands and legs of those who claim his death.”

Abubakr's (RA) attitude

Abu Bakr left his house at As-Sunh and came forth to the Mosque on a mare-back. At the Mosque, he dismounted and entered. He talked to nobody but went on till he entered ‘Aishah’s abode, and went directly to where the Messenger of Allâh (Peace be upon him) was. The Prophet (Peace be upon him) was covered with a Yemeni mantle. He uncovered his face and tended down, kissed him and cried. Then he said: “I sacrifice my father and mother for your sake. Allâh, verily, will not cause you to die
twice. You have just experienced the death that Allâh had ordained.” Then he went out and found ‘Umar talking to people. He said: “‘Umar, be seated.” ‘Umar refused to do
so. People parted ‘Umar and came towards Abu Bakr, who started a speech saying:
“And now, he who worships Muhammad (Peace be upon him). Muhammad is dead now. But he
who worships Allâh, He is Ever Living and He never dies. Allâh says: ‘Muhammad (Peace be upon him) is no more than a Messenger, and indeed (many) Messengers have passed away before him. If he dies or is killed, will you then turn back on your heels (as
disbelievers)? And he who turns back on his heels, not the least harm will he do to Allâh, and Allâh will give reward to those who are grateful.’” [3:1]

Ibn ‘Abbas said: “By Allâh, it sounded as if people had never heard such a Qur’ânic verse till Abu Bakr recited it as a reminder. So people started reciting it till there was no man who did not recite it.”

Ibn Al-Musaiyab said that ‘Umar had said: “By Allâh, as soon as I heard Abu Bakr say it, I fell down to the ground. I felt as if my legs had been unable to carry me so I collapsed when I heard him say it. Only then did I realize that Muhammad (Peace be upon him) had really died.”

Source:Ar Raheeq Al Makhtum