A verse and its Tafsir.
Allah the Exalted says:
“Lo! religion with Allah (is) the Surrender (to His Will and Guidance). Those who (formerly) received the Scripture differed only after knowledge came unto them, through transgression among themselves. Whoso disbelieveth the revelations of Allah (will find that) lo! Allah is swift at reckoning.” (3:19)
Ibn Kathir, may Allah have mercy on him, said:
This is an announcement from Allah the Exalted
that there is no religion in His sight that He will accept from anyone other than Islam.
Therefore, whoever meets Allah after the mission of Muhammad, peace and blessings of Allah be upon him,
following a religion other than his law,
it shall not be accepted from him.
Just as He said:
And whoever seeks a religion other than Islam,
it will never be accepted from him,
and in the Hereafter, he will be among the losers.