Allah has tested Ali’s (ع) heart with faith

It has been narrated from Ali (ع) who said:

جَاءَ سُهَيْلُ بنُ عَمْروٍ إِلَی رَسُولِ اللهِ (صلی الله علیه و آله) فَقَالَ: يَا مُحَمَّدُ، إِنَّهُ قَدْ خَرَجَ إِلَيْكَ اُنَاسٌ مِنْ أَرِقَّائِنَا لَيْسَ بِهِمْ لِلدِّينِ تَعَبُّدٌ فَارْدُدْهُمْ عَلَيْنَا

فَقَالَ أَبُو بَكْرٍ وَعُمَرُ: صَدَقَ يَا رَسُولَ الله!

فَقَالَ النَّبِيُّ (صلی الله علیه و آله): لَنْ تَنْتَهُوا يَا مَعْشَرَ قُرَيْشٍ! حَتَّی يَبْعَثَ اللهُ عَلَيْكُمْ رَجُلاً مِنِّي امْتَحَنَ اللهُ قَلْبَهُ لِلْإِيمَانِ يَضْرِبُ رِقَابَكُمْ عَلَی الدِّينِ وَأَنْتُمْ مُتَجَفِّلُونَ عَنْهُ إِجْفَالَ النِّعَمِ

فَقَالَ أَبُوبَكرٍ: أَنَا هُوَ يَا رَسُولَ الله؟

قَالَ: لَا

قَالَ عُمَرُ: أَنَا هُوَ يَا رَسُولَ اللهِ؟

قَالَ: لَا، وَلِكَنَّهُ خَاصِفُ النَّعْلِ

قَالَ: وَكَانَ فِي كَفِّ عَلِيٍّ نَعْلٌ يَخْصِفُهَا لِرَسُولِ اللهِ

Suhail bin Amr (together with some of the Quraish of Mecca) came to the Messenger of Allah (ص) and said: O Muhammad! A group of our children, brothers and slaves have come to you. They have come neither because they have any interest in religion nor because of understanding and wisdom. (In other words), they have no concern or affection towards religion. So return them to us.
Abu Bakr and Umar said: It is true, O Messenger of Allah!
However, the Prophet replied: O group of Quraish! You will never change and make amends until I send you a man whom Allah has tested his heart with faith, and he will strike your necks in accordance with divine instructions, and you will flee him like an unruly ostrich and will rebel.
Abu Bakr asked: Is that man me, O Messenger of Allah?
The Prophet (ص) said: No.
Omar said: Is it me, O Messenger of Allah?
The Prophet (ص) said: No, but he is the one who is mending shoes.
Suhail bin Amr says: And Ali had a shoe in his hand which he was patching for the Messenger of Allah (ص).