Sunan an-Nasa'i, Volume 2, Book 11, Hadith 896 (DarusSalam) ⓘ

It was narrated that Abu Hurairah said: "When the Messenger of Allah started to pray he would pause briefly. I said: 'May my father and mother be ransomed for you, O Messenger of Allah, what do you say when you pause briefly between the takbir and reciation?' He said: 'I say: Allahuma ba'id bayni wa bayna khatayaya kama ba'adta bayna al-mashriqi wal-maghrib; Allahumma naqqini min khatayaya kama yunaqqa ath-thawb al-abyad min ad-danas; Allahumma ighsilni min khatayaya bil ma'i wa ath-thalji wal-barad. (O Allah, put a great distance between me and my sins, as great as the distance You have made between the East and the West; O Allah, cleanse me of my sins as a white garment is cleansed from filth; O Allah, wash away my sins with water and snow and hail).'"

أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَنْبَأَنَا جَرِيرٌ، عَنْ عُمَارَةَ بْنِ الْقَعْقَاعِ، عَنْ أَبِي زُرْعَةَ بْنِ عَمْرِو بْنِ جَرِيرٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا افْتَتَحَ الصَّلاَةَ سَكَتَ هُنَيْهَةً فَقُلْتُ بِأَبِي أَنْتَ وَأُمِّي يَا رَسُولَ اللَّهِ مَا تَقُولُ فِي سُكُوتِكَ بَيْنَ التَّكْبِيرِ وَالْقِرَاءَةِ قَالَ ‏ "‏ أَقُولُ اللَّهُمَّ بَاعِدْ بَيْنِي وَبَيْنَ خَطَايَاىَ كَمَا بَاعَدْتَ بَيْنَ الْمَشْرِقِ وَالْمَغْرِبِ اللَّهُمَّ نَقِّنِي مِنْ خَطَايَاىَ كَمَا يُنَقَّى الثَّوْبُ الأَبْيَضُ مِنَ الدَّنَسِ اللَّهُمَّ اغْسِلْنِي مِنْ خَطَايَاىَ بِالْمَاءِ وَالثَّلْجِ وَالْبَرَدِ ‏" ‏ ‏.‏