Bilal ibn al-Harith reported: The Messenger of Allah, peace and blessings be upon him, said, “Verily, one of you may speak a word pleasing to Allah, thinking it does not amount to much, yet by it Allah decrees His pleasure with him until the day he meets Him. Verily, one of you may speak a word displeasing to Allah, thinking it does not amount to much, yet Allah decrees His displeasure with him until the day he meets Him meets.”
Source: Sunan al-Tirmidhī 2319
Grade: Sahih (authentic) according to Al-Tirmidhi
عَنْ بِلالِ بن الْحَارِث قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِنَّ أَحَدَكُمْ لَيَتَكَلَّمُ بِالْكَلِمَةِ مِنْ رِضْوَانِ اللَّهِ مَا يَظُنُّ أَنْ تَبْلُغَ مَا بَلَغَتْ فَيَكْتُبُ اللَّهُ لَهُ بِهَا رِضْوَانَهُ إِلَى يَوْمِ يَلْقَاهُ وَإِنَّ أَحَدَكُمْ لَيَتَكَلَّمُ بِالْكَلِمَةِ مِنْ سَخَطِ اللَّهِ مَا يَظُنُّ أَنْ تَبْلُغَ مَا بَلَغَتْ فَيَكْتُبُ اللَّهُ عَلَيْهِ بِهَا سَخَطَهُ إِلَى يَوْمِ يَلْقَاهُ
2319 سنن الترمذي كتاب الزهد باب في قلة الكلام
4/149 المحدث الترمذي خلاصة حكم المحدث حسن صحيح في سنن الترمذي