عَنْ أُمِّ سَلَمَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: كَانَ مِنْ آخِرِ وَصِيَّةِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((الصَّلَاةَ الصَّلَاةَ وَمَا مَلَكَتْ أَيْمَانُكُمْ)) حَتَّى جَعَلَ نَبِيُّ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يُلَجْلِجُهَا فِي صَدْرِهِ وَمَا يَفِيضُ بِهَا لِسَانُهُ
It is narrated from Sayyida Umm Salama (may Allah be pleased with her), she says: The last words of the will of the Messenger of Allah (peace and blessings be upon him) were: Adhere to the prayer, adhere to the prayer, and treat your slaves kindly. Until he (peace and blessings be upon him) began to repeat these words in his chest, and his tongue no longer had the strength to express them.