Sahih al-Bukhari 6682
Sahih al-Bukhari · Book 83: Oaths and Vows · If one says: "By Allah! I will not speak today"
Narrated Abu Huraira:
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ ، حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ ، حَدَّثَنَا عُمَارَةُ بْنُ الْقَعْقَاعِ ، عَنْ أَبِي زُرْعَةَ ، عَنْ أَبِي هُرَيْرَةَ ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " كَلِمَتَانِ خَفِيفَتَانِ عَلَى اللِّسَانِ، ثَقِيلَتَانِ فِي الْمِيزَانِ، حَبِيبَتَانِ إِلَى الرَّحْمَنِ سُبْحَانَ اللَّهِ وَبِحَمْدِهِ، سُبْحَانَ اللَّهِ الْعَظِيمِ " .
Allah's Messenger (ﷺ) said, "(The following are) two words (sentences or utterances) that are very easy for the tongue to say, and very heavy in the balance (of reward), and most beloved to the Gracious Almighty (And they are): Subhan Allahi wa bi-hamdihi; Subhan Allahi-l-'Adhim,"