Hadith: There is no Muslim who performs ablution well and then stands and prays two Rak‘ahs while focused on them with his heart and his face, except that Paradise will be guaranteed for him

عَنْ عُقْبَةَ بْنِ عَامِرٍ رضي الله عنه قَالَ: كَانَتْ عَلَيْنَا رِعَايَةُ الْإِبِلِ فَجَاءَتْ نَوْبَتِي فَرَوَّحْتُهَا بِعَشِيٍّ فَأَدْرَكْتُ رَسُولَ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَائِمًا يُحَدِّثُ النَّاسَ فَأَدْرَكْتُ مِنْ قَوْلِهِ:
«مَا مِنْ مُسْلِمٍ يَتَوَضَّأُ فَيُحْسِنُ وُضُوءَهُ، ثُمَّ يَقُومُ فَيُصَلِّي رَكْعَتَيْنِ، مُقْبِلٌ عَلَيْهِمَا بِقَلْبِهِ وَوَجْهِهِ، إِلَّا وَجَبَتْ لَهُ الْجَنَّةُ» قَالَ فَقُلْتُ: مَا أَجْوَدَ هَذِهِ، فَإِذَا قَائِلٌ بَيْنَ يَدَيَّ يَقُولُ: الَّتِي قَبْلَهَا أَجْوَدُ، فَنَظَرْتُ فَإِذَا عُمَرُ قَالَ: إِنِّي قَدْ رَأَيْتُكَ جِئْتَ آنِفًا، قَالَ: «مَا مِنْكُمْ مِنْ أَحَدٍ يَتَوَضَّأُ فَيُبْلِغُ - أَوْ فَيُسْبِغُ - الْوَضُوءَ ثُمَّ يَقُولُ: أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللهُ وَأَنَّ مُحَمَّدًا عَبْدُ اللهِ وَرَسُولُهُ إِلَّا فُتِحَتْ لَهُ أَبْوَابُ الْجَنَّةِ الثَّمَانِيَةُ يَدْخُلُ مِنْ أَيِّهَا شَاءَ».
[صحيح] - [رواه مسلم] - [صحيح مسلم: 234]

‘Uqbah ibn ‘Āmir (may Allah be pleased with him) reported: We were entrusted with the task of tending the camels. When I returned from my shift in the evening, I found the Messenger of Allah (may Allah's peace and blessings be upon him) standing and addressing the people. I heard him saying:
"There is no Muslim who performs ablution well and then stands and prays two Rak‘ahs while focused on them with his heart and his face, except that Paradise will be guaranteed for him." I said: "What a fine thing this is!" Thereupon, I heard someone in front of me saying: "What he said before it was even finer." I looked and it was ‘Umar ibn al-Khattāb, who said: "I see that you have just come." He said: "If anyone of you performs ablution thoroughly and then says, 'I bear witness that there is no god but Allah and that Muhammad is the servant and Messenger of Allah', the eight gates of Paradise will be opened for him and he may enter from whichever of them he wishes."
[Authentic hadith] - [Narrated by Muslim] - [Sahih Muslim - 234]

Explanation

The Prophet (may Allah's peace and blessings be upon him) pointed out two great virtues while addressing the people:
First: Whoever performs ablution well, thoroughly, completely, and perfectly in the prescribed manner, and gives each limb its due amount of water, and then says, I bear witness that there is no god but Allah and that Muhammad is the servant and Messenger of Allah, the eight gates of Paradise will be opened for him, and he may enter through whichever one he wishes.
Second: Whoever performs this complete and perfect ablution and then stands up and offers two Rak‘ahs, turning to them with his heart in sincerity and Khushū‘ (humility and focus), and submitting his face and all the parts of his body to Allah, Paradise will be guaranteed for him.