Sunan Abi Dawud Book 2, Hadith 390
I remember from the Messenger of Allah (ﷺ) two periods of silence. Sa'id said: We asked Qatadah: What are those two periods of silence? He said: (one) when he began his prayer, and (one) when he finished the recitation. Then he added: When he finished reciting (the closing verse of the Fatihah): "Not of those with whom Thou art angry, nor of who go astray."
Samurah ibn Jundub and Imran ibn Husayn had a discussion (about the periods of silence in prayer). Samurah then said that he remembered two periods of silence from the Messenger of Allah (ﷺ); one when he uttered the takbir and the other when he finished reciting: "Not of those with whom Thou art angry, nor of those who go astray" (i.7).
Samurah remembered that, but Imran ibn Husayn rejected it.
Then they wrote about it to Ubayy ibn Ka'b. He wrote a letter to them and gave a reply to them that Samurah remembered correctly.
The Messenger of Allah (ﷺ) kept silence between the takbir and the recitation of Qur’an. So I asked him, for whom I would give my father and mother as ransom: What do you say during you period of silence between the takbir and the recitation? He replied (that he said): O Allah, purify me from sins as a white garment is purified from filth. O Allah, wash away my sings with snow, water and hail.