Musnad Ahmad 175
It was narrated from Qais bin Marwan that he came to

'Umar and said:
I have come from Koofah, O Ameer al-­Mu'mineen, and I left behind in it a man who dictates the Mushaf From memory. ‘Umar got exceedingly angry and said: Who is he, woe to you? He said: 'Abdullah bin Mas'ood. ‘Umar began to calm down, and went back to normal, then he said: Woe to you, I do not know of anyone who is more qualified to do that than him, and I will tell you about that. The Messenger of Allah ﷺ used to stay up at night talking with Abu Bakr  رضي الله عنه discussing some affairs of the Muslims. He stayed up talking with him one night, and I was with him. The Messenger of Allah ﷺ went out, and we went out with him, and we saw a man standing and praying in the mosque. The Messenger of Allah ﷺ listened to his recitation, and as soon as we recognised him the Messenger of Allah ﷺ said: `Whoever would like to recite the Qur'an fresh as it was revealed, let him recite it according to the recitation of Ibn Umm 'Abd.` Then the same man sat and offered supplication (du'a') and the Messenger of Allah ﷺ started saying to him: `Ask, you will be given;ask, you will be given.” ‘Umar said: By Allah, I shall go to him tomorrow and tell hirm the glad tidings. I went to him the next morning to tell him the glad tidings, and I found that Abu Bakr had beaten me to it and given him the glad tidings. By Allah, I never competed with him to do good but he beat me to it.
حَدَّثَنَا أَبُو مُعَاوِيَةَ، حَدَّثَنَا الْأَعْمَشُ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، قَالَ جَاءَ رَجُلٌ إِلَى عُمَرَ رَضِيَ اللَّهُ عَنْهُ وَهُوَ بِعَرَفَةَ قَالَ أَبُو مُعَاوِيَةَ وَحَدَّثَنَا الْأَعْمَشُ عَنْ خَيْثَمَةَ عَنْ قَيْسِ بْنِ مَرْوَانَ أَنَّهُ أَتَى عُمَرَ رَضِيَ اللَّهُ عَنْهُ فَقَالَ جِئْتُ يَا أَمِيرَ الْمُؤْمِنِينَ مِنْ الْكُوفَةِ وَتَرَكْتُ بِهَا رَجُلًا يُمْلِي الْمَصَاحِفَ عَنْ ظَهْرِ قَلْبِهِ فَغَضِبَ وَانْتَفَخَ حَتَّى كَادَ يَمْلَأُ مَا بَيْنَ شُعْبَتَيْ الرَّحْلِ فَقَالَ وَمَنْ هُوَ وَيْحَكَ قَالَ عَبْدُ اللَّهِ بْنُ مَسْعُودٍ فَمَا زَالَ يُطْفَأُ وَيُسَرَّى عَنْهُ الْغَضَبُ حَتَّى عَادَ إِلَى حَالِهِ الَّتِي كَانَ عَلَيْهَا ثُمَّ قَالَ وَيْحَكَ وَاللَّهِ مَا أَعْلَمُهُ بَقِيَ مِنْ النَّاسِ أَحَدٌ هُوَ أَحَقُّ بِذَلِكَ مِنْهُ وَسَأُحَدِّثُكَ عَنْ ذَلِكَ كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَا يَزَالُ يَسْمُرُ عِنْدَ أَبِي بَكْرٍ رَضِيَ اللَّهُ عَنْهُ اللَّيْلَةَ كَذَاكَ فِي الْأَمْرِ مِنْ أَمْرِ الْمُسْلِمِينَ وَإِنَّهُ سَمَرَ عِنْدَهُ ذَاتَ لَيْلَةٍ وَأَنَا مَعَهُ فَخَرَجَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَخَرَجْنَا مَعَهُ فَإِذَا رَجُلٌ قَائِمٌ يُصَلِّي فِي الْمَسْجِدِ فَقَامَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَسْتَمِعُ قِرَاءَتَهُ فَلَمَّا كِدْنَا أَنْ نَعْرِفَهُ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَنْ سَرَّهُ أَنْ يَقْرَأَ الْقُرْآنَ رَطْبًا كَمَا أُنْزِلَ فَلْيَقْرَأْهُ عَلَى قِرَاءَةِ ابْنِ أُمِّ عَبْدٍ قَالَ ثُمَّ جَلَسَ الرَّجُلُ يَدْعُو فَجَعَلَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ لَهُ سَلْ تُعْطَهْ سَلْ تُعْطَهْ قَالَ عُمَرُ رَضِيَ اللَّهُ عَنْهُ قُلْتُ وَاللَّهِ لَأَغْدُوَنَّ إِلَيْهِ فَلَأُبَشِّرَنَّهُ قَالَ فَغَدَوْتُ إِلَيْهِ لِأُبَشِّرَهُ فَوَجَدْتُ أَبَا بَكْرٍ قَدْ سَبَقَنِي إِلَيْهِ فَبَشَّرَهُ وَلَا وَاللَّهِ مَا سَبَقْتُهُ إِلَى خَيْرٍ قَطُّ إِلَّا وَسَبَقَنِي إِلَيْهِ‏.‏