Hadith: Go and say to him: You are not from the people of Hellfire but from the people of Paradise

عَنْ ‌أَنَسِ بْنِ مَالِكٍ رَضِيَ اللهُ عَنْهُ:
أَنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ افْتَقَدَ ثَابِتَ بْنَ قَيْسٍ، فَقَالَ رَجُلٌ: يَا رَسُولَ اللهِ، أَنَا أَعْلَمُ لَكَ عِلْمَهُ، فَأَتَاهُ فَوَجَدَهُ جَالِسًا فِي بَيْتِهِ، مُنَكِّسًا رَأْسَهُ، فَقَالَ: مَا شَأْنُكَ؟ فَقَالَ شَرٌّ، كَانَ يَرْفَعُ صَوْتَهُ فَوْقَ صَوْتِ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ، فَقَدْ حَبِطَ عَمَلُهُ، وَهُوَ مِنْ أَهْلِ النَّارِ، فَأَتَى الرَّجُلُ فَأَخْبَرَهُ أَنَّهُ قَالَ كَذَا وَكَذَا، فَرَجَعَ الْمَرَّةَ الْآخِرَةَ بِبِشَارَةٍ عَظِيمَةٍ، فَقَالَ: «اذْهَبْ إِلَيْهِ فَقُلْ لَهُ: إِنَّكَ لَسْتَ مِنْ أَهْلِ النَّارِ، وَلَكِنْ مِنْ أَهْلِ الْجَنَّةِ».
[صحيح] - [متفق عليه] - [صحيح البخاري: 3613]

Anas ibn Mālik (may Allah be pleased with him) reported:
The Prophet (may Allah's peace and blessings be upon him) noticed the absence of Thābit ibn Qays. A man said: "O Messenger of Allah, I will bring you his news." So, he went to him and saw him sitting in his house, his head drooping (sadly). He said: "What is wrong with you?" Thābit said: "An evil situation; he used to raise his voice over the Prophet's voice, and so all his good deeds have been annulled, and he is from the people of Hellfire." The man returned and told the Prophet (may Allah's peace and blessings be upon him) that he had said such and such. The man went to Thābit again with glad tidings. He said: "Go and say to him: You are not from the people of Hellfire but from the people of Paradise."
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

The Prophet (may Allah's peace and blessings be upon him) noticed the absence of Thābit ibn Qays (may Allah be pleased with him) and asked about him. So, a man said: I will bring you his news and the reason behind his absence. He went to him and found him drooping his head sadly in his house. He asked him: What is wrong with you? Thābit told him about the evil circumstances he was experiencing, for he used to raise his voice over the Prophet's voice, and Allah threatened those who did so with the annulment of their deeds and that they would be among the people of Hellfire.
The man returned to the Prophet (may Allah's peace and blessings be upon him) and told him about that. Thereupon, the Prophet (may Allah's peace and blessings be upon him) ordered him to go back to Thābit and give him glad tidings that he was not one of the people of Hellfire but one of the people of Paradise. This is because his voice was naturally loud and because he was the speaker of the Messenger of Allah (may Allah's peace and blessings be upon him) and the speaker of the Ansār.