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.
muslim:32Isḥāq b. Manṣūr > Muʿādh b. Hishām from my father > Qatādah > Anas b. Mālik > Nabī Allāh ﷺ And Muʿādh b. Jabal Radīfuh > al-Raḥl > Yā Muʿādh

At thy beck and call, and at thy pleasure, Messenger of Allah. He again called out: Mu'adh, to which he (again) replied: At thy beck and call, and at thy pleasure. He (the Holy Prophet) addressed him (again): Mu'adh, to which he replied: At thy beck and call, and at thy pleasure, Messenger of Allah. Upon this he (the Holy Prophet) observed: If anyone testifies (sincerely from his heart) that there is no god but Allah, and that Muhammad is His bondsman and His messenger, Allah immuned him from Hell. He (Mu'adh) said: Messenger of Allah, should I not then inform people of it, so that they may be of good cheer? He replied: Then they would trust in it alone. Mu'adh told about it at the time of his death, to avoid sinning.  

مسلم:٣٢حَدَّثَنَا إِسْحَاقُ بْنُ مَنْصُورٍ أَخْبَرَنَا مُعَاذُ بْنُ هِشَامٍ قَالَ حَدَّثَنِي أَبِي عَنْ قَتَادَةَ قَالَ حَدَّثَنَا أَنَسُ بْنُ مَالِكٍ

أَنَّ نَبِيَّ اللَّهِ ﷺ وَمُعَاذُ بْنُ جَبَلٍ رَدِيفُهُ عَلَى الرَّحْلِ قَالَ يَا مُعَاذُ قَالَ لَبَّيْكَ رَسُولَ اللَّهِ وَسَعْدَيْكَ قَالَ يَا مُعَاذُ قَالَ لَبَّيْكَ رَسُولَ اللَّهِ وَسَعْدَيْكَ قَالَ يَا مُعَاذُ قَالَ لَبَّيْكَ رَسُولَ اللَّهِ وَسَعْدَيْكَ قَالَ مَا مِنْ عَبْدٍ يَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ إِلاَّ حَرَّمَهُ اللَّهُ عَلَى النَّارِ قَالَ يَا رَسُولَ اللَّهِ أَفَلاَ أُخْبِرُ بِهَا النَّاسَ فَيَسْتَبْشِرُوا قَالَ إِذًا يَتَّكِلُوا فَأَخْبَرَ بِهَا مُعَاذٌ عِنْدَ مَوْتِهِ تَأَثُّمًا  


See similar narrations below:

Collected by Bukhārī
bukhari:128Isḥāq b. Ibrāhīm > Muʿādh b. Hishām from my father > Qatādah > Anas b. Mālik

"Once Muʿadh was along with Messenger of Allah ﷺ as a companion rider. Messenger of Allah ﷺ said, "O Muʿadh bin Jabal." Muʿadh replied, "Labbaik and Saʿdaik. O Messenger of Allah ﷺ!" Again the Prophet ﷺ said, "O Muʿadh!" Muʿadh said thrice, "Labbaik and Saʿdaik, O Messenger of Allah ﷺ!" Messenger of Allah ﷺ said, "There is none who testifies sincerely that none has the right to be worshipped but Allah and Muhammad is his Apostle, except that Allah, will save him from the Hell-fire." Muʿadh said, "O Messenger of Allah ﷺ ! Should I not inform the people about it so that they may have glad tidings?" He replied, "When the people hear about it, they will solely depend on it." Then Muʿadh narrated the above-mentioned Hadith just before his death, being afraid of committing sin (by not telling the knowledge).  

البخاري:١٢٨حَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ قَالَ حَدَّثَنَا مُعَاذُ بْنُ هِشَامٍ قَالَ حَدَّثَنِي أَبِي عَنْ قَتَادَةَ قَالَ حَدَّثَنَا أَنَسُ بْنُ مَالِكٍ

أَنَّ النَّبِيَّ ﷺ وَمُعَاذٌ رَدِيفُهُ عَلَى الرَّحْلِ قَالَ يَا مُعَاذُ بْنَ جَبَلٍ قَالَ لَبَّيْكَ يَا رَسُولَ اللَّهِ وَسَعْدَيْكَ قَالَ يَا مُعَاذُ قَالَ لَبَّيْكَ يَا رَسُولَ اللَّهِ وَسَعْدَيْكَ ثَلاَثًا قَالَ مَا مِنْ أَحَدٍ يَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ صِدْقًا مِنْ قَلْبِهِ إِلاَّ حَرَّمَهُ اللَّهُ عَلَى النَّارِ قَالَ يَا رَسُولَ اللَّهِ أَفَلاَ أُخْبِرُ بِهِ النَّاسَ فَيَسْتَبْشِرُوا قَالَ إِذًا يَتَّكِلُوا وَأَخْبَرَ بِهَا مُعَاذٌ عِنْدَ مَوْتِهِ تَأَثُّمًا