This verse is: "Verily, those who conceal the clear signs and the guidance which we have sent down...)" (2:159). I heard the Prophet ﷺ saying, 'If a man performs ablution perfectly and then offers the compulsory congregational prayer, Allah will forgive his sins committed between that (prayer) and the (next) prayer till he offers it.  

أَلاَ أُحَدِّثُكُمْ حَدِيثًا لَوْلاَ آيَةٌ مَا حَدَّثْتُكُمُوهُ سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ لاَ يَتَوَضَّأُ رَجُلٌ فَيُحْسِنُ وُضُوءَهُ وَيُصَلِّي الصَّلاَةَ إِلاَّ غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلاَةِ حَتَّى يُصَلِّيَهَا قَالَ عُرْوَةُ الآيَةُ {إِنَّ الَّذِينَ يَكْتُمُونَ مَا أَنْزَلْنَا مِنَ الْبَيِّنَاتِ}  

By Allah, I am narrating to you a hadith had there not been this verse in the Book of Allah. I would not have narrated it to you. Verily I heard the Messenger of Allah ﷺ say: Not a person is there who performed ablution, and did it well, then offered prayer, but his sins (which he committed) were not pardoned between the prayer that he offered and the next one. 'Urwa said: The verse is this:" Those who suppress the clear proofs and the guidance which We have sent down"... to His words:" the Cursers" (ii. 15).  

فَلَمَّا تَوَضَّأَ عُثْمَانُ قَالَ وَاللَّهِ لأُحَدِّثَنَّكُمْ حَدِيثًا وَاللَّهِ لَوْلاَ آيَةٌ فِي كِتَابِ اللَّهِ مَا حَدَّثْتُكُمُوهُ إِنِّي سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ لاَ يَتَوَضَّأُ رَجُلٌ فَيُحْسِنُ وُضُوءَهُ ثُمَّ يُصَلِّي الصَّلاَةَ إِلاَّ غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلاَةِ الَّتِي تَلِيهَا قَالَ عُرْوَةُ الآيَةُ { إِنَّ الَّذِينَ يَكْتُمُونَ مَا أَنْزَلْنَا مِنَ الْبَيِّنَاتِ وَالْهُدَى} إِلَى قَوْلِهِ { اللاَّعِنُونَ}  

I heard from 'Uthman b. 'Affan and he was in the courtyard of the mosque, when the Mu'adhdhin (announcer of the prayer) came to him at the time of afternoon prayer. So the ('Uthman) called for the ablution water and performed ablution and then said: By Allah, I am narrating to you a hadith. If there were not a verse in the Book of Allah, I would have never narrated it to you. I heard Messenger of Allah ﷺ say: If a Muslim performs ablution and does it well and offers prayer, all his (sins) daring the period from one prayer to another would be pardoned by Allah.  

سَمِعْتُ عُثْمَانَ بْنَ عَفَّانَ وَهُوَ بِفِنَاءِ الْمَسْجِدِ فَجَاءَهُ الْمُؤَذِّنُ عِنْدَ الْعَصْرِ فَدَعَا بِوَضُوءٍ فَتَوَضَّأَ ثُمَّ قَالَ وَاللَّهِ لأُحَدِّثَنَّكُمْ حَدِيثًا لَوْلاَ آيَةٌ فِي كِتَابِ اللَّهِ مَا حَدَّثْتُكُمْ إِنِّي سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ لاَ يَتَوَضَّأُ رَجُلٌ مُسْلِمٌ فَيُحْسِنُ الْوُضُوءَ فَيُصَلِّي صَلاَةً إِلاَّ غَفَرَ اللَّهُ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلاَةِ الَّتِي تَلِيهَا  

"I heard the Messenger of Allah ﷺ say: 'There is no man who performs Wudu' and does it well, then prays, but when he prays it, he will be forgiven whatever (sins he commits) between that and the next prayer."  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ مَا مِنِ امْرِئٍ يَتَوَضَّأُ فَيُحْسِنُ وُضُوءَهُ ثُمَّ يُصَلِّي الصَّلاَةَ إِلاَّ غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلاَةِ الأُخْرَى حَتَّى يُصَلِّيَهَا  

My father told me that Humran told him: ʿUthman ؓ did wudoo’ in al-Balat (a paved area in Madinah) then he said, i shall tell you a hadeeth that I heard from the Messenger of Allah ﷺ . Were it not for a verse in the Book of Allah, I would not have told you it. I heard the Prophet ﷺ say: ʿWhoever does wudoo’ and does it well, then goes in and prays, his sins between that prayer and the next will be forgiven, until he prays [the second prayer].”  

لَأُحَدِّثَنَّكُمْ حَدِيثًا سَمِعْتُهُ مِنْ رَسُولِ اللهِ ﷺ لَوْلَا آيَةٌ فِي كِتَابِ اللهِ مَا حَدَّثْتُكُمُوهُ سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ مَنْ تَوَضَّأَ فَأَحْسَنَ الْوُضُوءَ ثُمَّ دَخَلَ فَصَلَّى غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلاةِ الْأُخْرَى حَتَّى يُصَلِّيَهَا  

My father told me that Humran told him: ʿUthman ؓ did wudoo’ in al-Balat (a paved area in Madinah) then he said, i shall tell you a hadeeth that I heard from the Messenger of Allah ﷺ . Were it not for a verse in the Book of Allah, I would not have told you it. I heard the Prophet ﷺ say: ʿWhoever does wudoo’ and does it well, then goes in and prays, his sins between that prayer and the next will be forgiven, until he prays [the second prayer].” (Using translation from Aḥmad 400)   

لَأُحَدِّثَنَّكُمْ حَدِيثًا لَوْلَا آيَةٌ فِي كِتَابِ اللَّهِ لَمَّا حَدَّثْتُكُمُوهُ ثُمَّ قَالَ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ «مَا مِنِ امْرِئٍ يَتَوَضَّأُ فَيُحْسِنُ الْوُضُوءَ ثُمَّ يُصَلِّي الصَّلَاةَ إِلَّا غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلَاةِ الْأُخْرَى حَتَّى يُصَلِّيَهَا»  

"I heard the Messenger of Allah ﷺ say: 'There is no man who performs Wudu' and does it well, then prays, but when he prays it, he will be forgiven whatever (sins he commits) between that and the next prayer." (Using translation from Nasāʾī 146)  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «مَا مِنَ امْرِئٍ يَتَوَضَّأُ فَيُحْسِنُ وُضُوءَهُ ثُمَّ يُصَلِّي الصَّلَاةَ إِلَّا غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلَاةِ الْأُخْرَى حَتَّى يُصَلِّيَهَا»  

[Machine] "And he said: 'This is how I saw the Messenger of Allah ﷺ make ablution, then he said: I heard the Messenger of Allah ﷺ saying: There is no man who performs ablution and does it well, then he prays, except that Allah forgives him for his sins between that prayer and the next, until he prays it.'"  

وَقَالَ هَكَذَا رَأَيْتُ رَسُولَ اللهِ ﷺ يَتَوَضَّأُ ثُمَّ قَالَ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ مَا مِنْ رَجُلٍ يَتَوَضَّأُ فَيُحْسِنُ الْوُضُوءَ ثُمَّ يُصَلِّي إِلَّا غَفَرَ اللهُ لَهُ مَا بَيْنَهُ وَبَيْنَ الصَّلَاةِ الْأُخْرَى حَتَّى يُصَلِّيَهَا  

"مَا مِنْ رَجُلٍ يَتَوَضَّأُ فَيُحْسِن الوُضُوءَ ثُمَّ يُصَلِّي إِلا غَفَرَ اللهُ لَهُ مَا بَينَه وَبَينَ الصَّلاةِ الأخْرَى حَتَّى يُصلِّيهَا".  

"مَا من امْرئٍ يَتَوَضَّأ فَيُحْسِنُ وُضُوءَه، ثُمَّ يُصَلِّي الصَّلاةَ، إلا غُفِر لَهُ مَا بَينَه وَبَينَ الصَّلاةِ الأَخْرَى حَتَّى يُصَلّيهَا".