Prophetic traditions make this point perfectly clear: everyone who hears about Muhammad ﷺ is bound to believe in him, follow him, and relinquish any previous dispensation whose validity ended with the coming of Muhammad, the Seal of the Prophets. He ﷺ said, “By the One in whose hand is my soul, no one from this community—whether Jew or Christian—who hears of me, then dies without believing in what I have been sent with, shall escape being among the people of the Fire.” ⦗1⦘
A believer from the People of the Scripture who follows Muhammad ﷺ will receive his reward twice over. Abu Musa al-Ashʿari reports that the Messenger of Allah ﷺ said, “Three types of people will be given their reward twice: (i) a man from the People of the Scripture who believed in his own prophet, then encountered the Prophet ﷺ, believed in him, followed him, and affirmed him—he shall have a double reward; (ii) a slave who fulfills the right of Allah, exalted is He, and the right of his master—he shall have a double reward; and (iii) a man who owned a slave-girl, fed her well and treated her kindly, then educated her and trained her in good manners, then freed her and married her—he shall have a double reward.” ⦗2⦘
When Jesus (peace be upon him) descends near the end of time, just before the Hour, he will rule according to the law of Muhammad ﷺ. What excuse, then, will the People of the Scripture have for not believing in him and following him? Abu Hurayrah reports: I heard the Messenger of Allah ﷺ say, “By the One in whose hand is my soul, the son of Mary is soon to descend among you as a just ruler: he will break the cross, kill the swine, abolish the jizya tax⦗3⦘, and wealth will overflow until no one will accept it.” ⦗4⦘