فضائل التوحيد
Anas (may Allah be pleased with him) reported: The Prophet (may Allah's peace and blessings be upon him) was riding a mount with Mu‘ādh behind him, when he said: "O Mu‘ādh!" Mu‘ādh replied: "Here I am at your service, O Messenger of Allah." He again said: "O Mu‘ādh!" Mu‘ādh replied: "Here I am at your service, O Messenger of Allah." He said for the third time: "O Mu‘ādh!" Mu‘ādh replied: "Here I am at your service, O Messenger of Allah." Thereupon, the Prophet (may Allah's peace and blessings be upon him) said: "There is no one who bears witness that there is no god but Allah and that Muhammad is His slave and Messenger, sincerely from his heart, but Allah will forbid him to the Fire." Mu‘ādh said: "O Messenger of Allah, should I not inform the people of that so that they may rejoice?" He replied: "They would then rely on this alone (and stop doing good deeds altogether)." Mu‘ādh narrated this Hadīth at the time of his death, to avoid the sin (of concealing knowledge).
عن أنس -رضي الله عنه-: أن النبي -صلى الله عليه وسلم- ومعاذ رديفه على الرَّحْلِ، قال: «يا معاذ» قال: لبَّيْكَ يا رسول الله وسَعْدَيْكَ، قال: «يا معاذ» قال: لَبَّيْكَ يا رسول الله وسَعْدَيْكَ، قال: «يا معاذ» قال: لبَّيْكَ يا رسول اللهِ وسَعْدَيْكَ، ثلاثا، قال: «ما من عبد يشهد أن لا إله إلا الله، وأَنَّ محمدا عبده ورسوله صِدْقًا من قلبه إلَّا حرمه الله على النار» قال: يا رسول الله، أفلا أُخْبِر بها الناس فَيَسْتَبْشِرُوا؟ قال: «إِذًا يتكلوا» فأخبر بها معاذ عند موته تَأَثُّمًا.
شرح الحديث :
Mu‘ādh (may Allah be pleased with him) was sitting behind the Prophet (may Allah's peace and blessings be upon him) on the mount when the Prophet said: "O Mu‘ādh!" He replied: "Here I am at your service, O Messenger of Allah," meaning: Here I am at your service and I will obey you time after time. The Prophet called Mu‘ādh thrice and Mu‘ādh gave the same reply each time, then the Prophet said: There is no slave (of Allah) who bears witness that there is no god but Allah and that Muhammad is His slave and Messenger, saying it sincerely from his heart not just with his tongue, but Allah will safeguard him from dwelling eternally in the Hellfire. Mu‘ādh said: O Messenger of Allah, should I not then relay this knowledge to the people to make them rejoice. The Prophet (may Allah's peace and blessings be upon him) replied: No, so that they would not rely on that alone and stop doing good deeds. Mu‘ādh disclosed this Hadīth at the end of his life for fear of committing the sin of concealing knowledge.