Ruling on those who say that Islam and faith are not limited to the message of Prophet Muhammad (blessings and peace of Allaah be upon him)
Question

                Some people say that Islam and faith are not limited to the message of our Prophet Muhammad (blessings and peace of Allaah be upon him) only, rather Islam and faith may be attained by every person who worships Allaah in whatever way both before and after the blessed mission of Muhammad (lettings and peace of Allaah be upon him). What is your comment?.
Praise be to Allah.
    As for the time before the mission of the Prophet Muhammad 
    (blessings and peace of Allaah be upon him), everyone who believed in the 
    previous Messengers, is one of the people of Paradise. Whoever believed in 
    Moosa, ‘Eesa, Hood, Saalih, in all the Messengers, was one of the people of 
    Paradise if he died believing in that. But after the mission of Muhammad 
    (blessings and peace of Allaah be upon him), no one is among the people of 
    Paradise except those who followed Muhammad (blessings and peace of Allaah 
    be upon him). All of the people of Earth after the sending of Muhammad 
    (blessings and peace of Allaah be upon him) have no way of salvation except 
    by following Muhammad (blessings and peace of Allaah be upon him). The 
    Prophet (blessings and peace of Allaah be upon him) said: “All of my ummah 
    will enter Paradise except those who refuse.” It was said: O Messenger of 
    Allaah, who refuses? He said: “Those who obey me will enter Paradise, and 
    those who disobey me have refused.” So the followers of the Prophet Muhammad 
    (blessings and peace of Allaah be upon him) are those who will enter 
    Paradise, to the exclusion of others. And the Prophet (blessings and peace 
    of Allaah be upon him) said: “By the one in whose hand is my soul, no one of 
    this nation hears of me, Jew or Christian, then dies without believing in 
    that with which I have been sent, but he will be one of the people of the 
    Fire.” So after the sending of Muhammad (blessings and peace of Allaah be 
    upon him), no one can be one of the people of Paradise except those who 
    follow him. As for those who hear about him and disbelieve in him, and do 
    not believe in him, they are people of the Fire. As for those who do not 
    hear about the Prophet (blessings and peace of Allaah be upon him) or the 
    Messenger or of the Qur’aan, they come under the same ruling as those who 
    lived in the intervals between Prophets. Their case will be up to Allaah on 
    the Day of Resurrection; Allaah will test them and those who pass the test 
    will enter Paradise, and those who do not pass the test will enter Hell -- 
    we ask Allaah to keep us safe and sound. As for those who hear about the 
    message of the Prophet (blessings and peace of Allaah be upon him) and hear 
    about the Qur’aan and do not believe, they will be among the people of the 
    Fire. The one who does not regard the disbelievers as disbelievers is like 
    them. It is essential to regard as disbelievers the one who does not believe 
    in Allaah, and to regard as a disbeliever the one who disbelieves in Him. 
    Hence it is proven in the saheeh hadeeth that the Prophet (blessings and 
    peace of Allaah be upon him) said: “The one who believes in the oneness of 
    Allaah and disbelieves in that which is worshipped instead of Allaah, his 
    wealth and his blood become haraam, and his reckoning will be with Allaah.” 
    And Allaah, may He be glorified and exalted, says (interpretation of the 
    meaning):

    “Whoever disbelieves in Taaghoot [false gods etc.] and 
    believes in Allaah, then he has grasped the most trustworthy handhold that 
    will never break. And Allaah is All-Hearer, All-Knower”

    [al-Baqarah 2:256]

    So it is essential to believe in Allaah, believe in his 
    Oneness, and be sincere towards Him, and to believe that the believers are 
    following the true faith. And it is essential to regard as disbelievers 
    those disbelievers who heard of sharee’ah but did not believe, like the 
    Jews, the Christians, the Magians, the Communists and others who exist today 
    or who existed previously. Whoever hears the message of Allaah and does not believe is one of the people of Hell -- we ask Allaah to keep us safe and sound. End quote.