سنن النسائي

It was narrated that Abu Hurairah said: "When the Messenger of Allah (ﷺ) 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).'"