كتاب الذكر والدعاء والتوبة والاستغفار
48  
The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness
(13)
Chapter: It Is Recommend To Lower One's Voice When Saying Remembrance, Except In The Cases Where It Is Commanded To Raise The Voice Such As The Talbiyah Etc. It Is Recommend To Say A Great Deal, "There Is No Power And No Strength Except With Allah"
(13)
باب اسْتِحْبَابِ خَفْضِ الصَّوْتِ بِالذِّكْرِ
Sahih Muslim 2704 e

Abu Musa reported:

We were along with Allah's Apostle (ﷺ) on a journey; the rest of the hadith is the same as transmitted by A'sim.
حَدَّثَنَا خَلَفُ بْنُ هِشَامٍ، وَأَبُو الرَّبِيعِ، قَالاَ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ أَيُّوبَ، عَنْ أَبِي، عُثْمَانَ عَنْ أَبِي مُوسَى، قَالَ كُنَّا مَعَ النَّبِيِّ صلى الله عليه وسلم فِي سَفَرٍ ‏.‏ فَذَكَرَ نَحْوَ حَدِيثِ عَاصِمٍ ‏.‏
Reference : Sahih Muslim 2704e
In-book reference : Book 48, Hadith 60
USC-MSA web (English) reference : Book 35, Hadith 6530
  (deprecated numbering scheme)