I heard the Messenger of Allah ﷺ say, "There is no heart that is not between two of the fingers of the Lord of the worlds. If He wills to keep it firm, He keeps it firm, and if He wills to make it deviate, He makes it deviate."He used to say, "Turner of hearts, make our hearts firm upon Your religion. The scale is in the hand of the Most Merciful , He lowers it and raises it."
حدثنا الوليد بن مسلم قال سمعت يعني ابن جابر يقول حدثني بسر بن عبيد الله الحضرمي أنه سمع أبا إدريس الخولاني يقول سمعت
سمعت رسول الله ﷺ يقول ما من قلب إلا وهو بين أصبعين من أصابع رب العالمين إن شاء أن يقيمه أقامه وإن شاء أن يزيغه أزاغه وكان يقول يا مقلب القلوب ثبت قلوبنا على دينك والميزان بيد الرحمن عز وجل يخفضه ويرفعه
Its isnad is sahih. Its narrators are famous, reliable memorizers, and Busr bin Abdullah Hadrami is a reliable memorizer. The hadith was narrated by Ibn Majah 1/72, no. 199, in the introduction, chapter on what the Jahmiyyah denied, and by Ibn Hibban, 600, no. 2416, and Hakim graded it sahih, 1/545, and Dhahabi endorsed him.