Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ibnmajah:2099Hishām b. ʿAmmār > Baqiyyah > ʿAbdullāh b. Muḥarrar > Qatādah > Anas

"If that happens, I will be a Jew." The Messenger of Allah ﷺ said: 'That is guaranteed."  

ابن ماجة:٢٠٩٩حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ حَدَّثَنَا بَقِيَّةُ عَنْ عَبْدِ اللَّهِ بْنِ مُحَرَّرٍ عَنْ قَتَادَةَ عَنْ أَنَسٍ قَالَ

سَمِعَ النَّبِيُّ ﷺ رَجُلاً يَقُولُ أَنَا إِذًا لَيَهُودِيٌّ فَقَالَ رَسُولُ اللَّهِ ﷺ وَجَبَتْ