"When the Messenger of Allah ﷺ started Salah, he would remain silent for a short while. I said: 'May my father and mother be ransomed for you, O Messenger of Allah! What do you say when you remain silent between the Takbir and the recitation (in the Salah)?' He said: 'I say: Allahumma ba'id baini was baina khatayaya kama ba'adta baina al-mashriq wal-maghrib; Allahumma naqqini min khatayaya kama yunaqqath-thawb al-abyad min ad-danas; Allahummaghsilni min khatayaya bith-thalji wal-ma'i wal-barad (O Allah, out 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 of sin as a white garment is cleansed from filth; Wash away my sins with snow, water, and hail)'." (Using translation from Nasāʾī 60)  

كَانَ رَسُولُ اللهِ ﷺ إِذَا اسْتَفْتَحَ الصَّلَاةَ سَكَتَ هُنَيْهَةً فَقُلْتُ بِأَبِي أَنْتَ وَأُمِّي يَا رَسُولَ اللهِ مَا تَقُولُ فِي سُكُوتِكَ بَيْنَ التَّكْبِيرِ وَالْقِرَاءَةِ؟ قَالَ أَقُولُ «اللهُمَّ بَاعِدْ بَيْنِي وَبَيْنَ خَطَايَايَ كَمَا بَاعَدْتَ بَيْنَ الْمَشْرِقِ وَالْمَغْرِبِ اللهُمَّ نَقِّنِي مِنْ خَطَايَايَ كَمَا يُنَقَّى الثَّوْبُ الْأَبْيَضُ مِنَ الدَّنَسِ اللهُمُ اغْسِلْنِي مِنْ خَطَايَايَ بِالثَّلْجِ وَالْمَاءِ وَالْبَرَدِ»