Opening supplication in prayer — distance from sins
اللّهُـمَّ باعِـدْ بَيـني وَبَيْنَ خَطـايايَ كَما...
اللّهُـمَّ باعِـدْ بَيـني وَبَيْنَ خَطـايايَ كَما باعَدْتَ بَيْنَ المَشْرِقِ وَالمَغْرِب، اللّهُـمَّ نَقِّنـي مِنْ خَطايايَ كَمـا يُـنَقَّى الثَّـوْبُ الأَبْيَضُ مِنَ الدَّنَسْ، اللّهُـمَّ اغْسِلْنـي مِنْ خَطايـايَ بِالثَّلـجِ وَالمـاءِ وَالْبَرَدْ
Allahumma baAAid baynee wabayna khatayaya kama baAAadta baynal-mashriqi walmaghrib, allahumma naqqinee min khatayaya kama yunaqqath-thawbul-abyadu minad-danas, allahummagh-silnee min khatayaya biththalji walma-i walbarad
Translation
O Allah, distance me from my sins just as You have distanced The East from The West. O Allah, purify me of my sins as a white robe is purified of filth. O Allah, cleanse me of my sins with snow, water, and ice.
When to recite
Opening supplication after takbeer at the start of prayer.
Source / Reference
Al-Bukhari 1/181, Muslim 1/419