Hadithcore
Hadith #2103330

Narrated Abu Hurairah (RA) Allah's Messenger (ﷺ) used to keep silent - between the opening Takbir of the prayer and the recitation of the Qur'an - for a short while. Then, I asked him (about that) and he replied, "I say, 'O Allah! Keep me apart from my sins (faults) as you have kept apart the east and west. O Allah clean me from my sins as a white garment is cleaned from dirt. O Allah wash me of my sins with water, snow and hail." [Agreed upon].

وَعَنْ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- قَالَ : { كَانَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-إِذَا كَبَّرَ لِلصَّلَاةِ سَكَتَ هُنَيَّةً , قَبْلِ أَنْ يَقْرَأَ , فَسَأَلْتُهُ , فَقَالَ : "أَقُولُ : اَللَّهُمَّ بَاعِدْ بَيْنِي وَبَيْنَ خَطَايَايَ كَمَا بَاعَدْتَ بَيْنَ اَلْمَشْرِقِ وَالْمَغْرِبِ , اَللَّهُمَّ نقِّنِي مِنْ خَطَايَايَ كَمَا يُنَقَّى اَلثَّوْبُ اَلْأَبْيَضُ مِنْ اَلدَّنَسِ , اَللَّهُمَّ اِغْسِلْنِي مِنْ خَطَايَايَ بِالْمَاءِ وَالثَّلْجِ وَالْبَرَدِ } مُتَّفَقٌ عَلَيْهِ [1]‏

References2 variants
Sunnah.com reference
Book 2, Hadith 150
Arabic/English book reference
Book 2, Hadith 269