رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 693
The Book of Good Manners
Excellence of Meeting with a Smiling Countenance and Politeness in Speech
وَعَنْ أَبِي هُرَيْرَةَ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: والكلمة الطيبة صدقة ((مُتَّفَقٌ عَلَيْهِ)) وهو بعض حَدِيث تقدم بطوله.
Abu Hurairah (May Allah be pleased with him) reported: The Prophet (ﷺ) said, "It is also charity to utter a good word." [Al- Bukhari and Muslim]. It is part of a narration that has preceded in its entirety.
Riyad as-Salihin, 693