By the One in Whose Hand Muhammad's soul is, there is nobody of this Ummah (community), whether they be Jewish or Christian, who hears of me and then dies without believing in what I was sent with except that he will be among the people of ...

It demonstrates the generality of the Prophet's message that addresses the whole world, the obligation of following him, and the fact that his Shariah has abrogated all the previous legislations.
Whoever disbelieves in the Prophet (may Allah's peace and blessings be upon him), his belief in other prophets (peace be upon all of them) will not be of any avail to him.
Those who have not heard about the Prophet (may Allah's peace and blessings be upon him) and the call of Islam has not reached them are excused and their case in the Hereafter is left to Allah Almighty.
A person can embrace Islam even shortly before death, even if he is in severe illness, so long as the soul did not reach the throat (did not witness death).
Belief in the soundness of the disbelievers' religion, including the Jews and the Christians, is disbelief.
The reference in this Hadīth to the Jews and the Christians indicates that the ruling includes the people of other faiths as well. If this is the case with the Jews and the Christians, who received divine scriptures, then it is more emphatic for those who have no scripture, for everyone must embrace Islam and obey its Messenger (may Allah's peace and blessings be upon him).