Whenever I heard a hadith from the Messenger of Allah ﷺ, Allah would benefit me by it as He willed. But when someone else narrated to me from him, I would make him swear an oath, and if he swore, I would believe him. Abu Bakr narrated to me, and Abu Bakr spoke the truth.He said, the Messenger of Allah ﷺ said, "There is no man who commits a sin, then performs ablution and does it well, then prays two units of prayer," and Masaar said, "then prays and seeks Allah's forgiveness, except that Allah forgives him."
حدثنا أبو بكر بن أبي شيبة ونصر بن علي قالا حدثنا وكيع حدثنا مسعر وسفيان عن عثمان بن المغيرة الثقفي عن علي بن ربيعة الوالبي عن أسماء بن الحكم الفزاري
كنت إذا سمعت من رسول الله ﷺ حديثا ينفعني الله بما شاء منه وإذا حدثني عنه غيره استحلفته فإذا حلف صدقته وإن أبا بكر حدثني وصدق أبو بكر قال قال رسول الله ﷺ ما من رجل يذنب ذنبا فيتوضأ فيحسن الوضوء ثم يصلي ركعتين وقال مسعر ثم يصلي ويستغفر الله إلا غفر الله له
Sourcing, [its chain is hasan]. Abu Dawud narrated it in Witr, chapter on seeking forgiveness, no. 1521, from the hadith of Uthman bin Mughira through this route, and Tirmidhi graded it hasan, no. 406, as did Ibn Adi and others, while Ibn Hibban graded it sahih.