Jami` at-Tirmidhi 3587
`Asim bin Kulaib Al-Jarmi narrated from his father, from his grandfather, who said:
“I entered upon the Prophet (ﷺ) while he was praying and he had placed his left hand on his left thigh, and he had placed his right hand on his right thigh, and clasped his fingers, and extended his index finger, and he was saying: ‘O changer of the hearts, make my heart firm upon Your religion (Yā muqallibal-qulūbi thabbit qalbī `alā dīnik).’”
حَدَّثَنَا عُقْبَةُ بْنُ مُكْرَمٍ، حَدَّثَنَا سَعِيدُ بْنُ سُفْيَانَ الْجَحْدَرِيُّ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَعْدَانَ، أَخْبَرَنِي عَاصِمُ بْنُ كُلَيْبٍ الْجَرْمِيُّ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، قَالَ دَخَلْتُ عَلَى النَّبِيِّ صلى الله عليه وسلم وَهُوَ يُصَلِّي وَقَدْ وَضَعَ يَدَهُ الْيُسْرَى عَلَى فَخِذِهِ الْيُسْرَى وَوَضَعَ يَدَهُ الْيُمْنَى عَلَى فَخِذِهِ الْيُمْنَى وَقَبَضَ أَصَابِعَهُ وَبَسَطَ السَّبَّابَةَ وَهُوَ يَقُولُ ‏
"‏ يَا مُقَلِّبَ الْقُلُوبِ ثَبِّتْ قَلْبِي عَلَى دِينِكَ ‏"‏ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ غَرِيبٌ مِنْ هَذَا الْوَجْهِ ‏.‏