Sahih Muslim , Book 48, Hadith 117 (In-Book) ⓘ

Abu Dharr reported that Allah's Messenger was asked as to which words were the best. He said: Those for which Allah made a choice for His Angels and His servants (and the words are):" Hallowed be Allah and praise is due to Him."

حَدَّثَنَا زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا حَبَّانُ بْنُ هِلاَلٍ، حَدَّثَنَا وُهَيْبٌ، حَدَّثَنَا سَعِيدٌ الْجُرَيْرِيُّ، عَنْ أَبِي عَبْدِ اللَّهِ الْجِسْرِيِّ، عَنِ ابْنِ الصَّامِتِ، عَنْ أَبِي ذَرٍّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم سُئِلَ أَىُّ الْكَلاَمِ أَفْضَلُ قَالَ ‏ "‏ مَا اصْطَفَى اللَّهُ لِمَلاَئِكَتِهِ أَوْ لِعِبَادِهِ سُبْحَانَ اللَّهِ وَبِحَمْدِهِ ‏" ‏ ‏.‏