Sahih al-Bukhari 3009
Narrated Sahl:
On the day (of the battle) of Khaibar the Prophet (ﷺ) said, "Tomorrow I will give the flag to somebody 
who will be given victory (by Allah) and who loves Allah and His Apostle and is loved by Allah and 
His Apostle." So, the people wondered all that night as to who would receive the flag and in the 
morning everyone hoped that he would be that person. Allah's Messenger (ﷺ) asked, "Where is `Ali?" He 
was told that `Ali was suffering from eye-trouble, so he applied saliva to his eyes and invoked Allah 
to cure him. He at once got cured as if he had no ailment. The Prophet (ﷺ) gave him the flag. `Ali said, 
"Should I fight them till they become like us (i.e. Muslim)?" The Prophet (ﷺ) said, "Go to them patiently 
and calmly till you enter the land. Then, invite them to Islam, and inform them what is enjoined upon 
them, for, by Allah, if Allah gives guidance to somebody through you, it is better for you than 
possessing red camels."
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا يَعْقُوبُ بْنُ عَبْدِ الرَّحْمَنِ بْنِ مُحَمَّدِ بْنِ عَبْدِ اللَّهِ بْنِ عَبْدٍ الْقَارِيُّ، عَنْ أَبِي حَازِمٍ، قَالَ أَخْبَرَنِي سَهْلٌ ـ رضى الله عنه يَعْنِي ابْنَ سَعْدٍ ـ قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم يَوْمَ خَيْبَرَ ‏"‏ لأُعْطِيَنَّ الرَّايَةَ غَدًا رَجُلاً يُفْتَحُ عَلَى يَدَيْهِ، يُحِبُّ اللَّهَ وَرَسُولَهُ، وَيُحِبُّهُ اللَّهُ وَرَسُولُهُ ‏"‏‏.‏ فَبَاتَ النَّاسُ لَيْلَتَهُمْ أَيُّهُمْ يُعْطَى فَغَدَوْا كُلُّهُمْ يَرْجُوهُ فَقَالَ ‏"‏ أَيْنَ عَلِيٌّ ‏"‏‏.‏ فَقِيلَ يَشْتَكِي عَيْنَيْهِ، فَبَصَقَ فِي عَيْنَيْهِ وَدَعَا لَهُ، فَبَرَأَ كَأَنْ لَمْ يَكُنْ بِهِ وَجَعٌ، فَأَعْطَاهُ فَقَالَ أُقَاتِلُهُمْ حَتَّى يَكُونُوا مِثْلَنَا‏.‏ فَقَالَ ‏"‏ انْفُذْ عَلَى رِسْلِكَ حَتَّى تَنْزِلَ بِسَاحَتِهِمْ، ثُمَّ ادْعُهُمْ إِلَى الإِسْلاَمِ، وَأَخْبِرْهُمْ بِمَا يَجِبُ عَلَيْهِمْ، فَوَاللَّهِ لأَنْ يَهْدِيَ اللَّهُ بِكَ رَجُلاً خَيْرٌ لَكَ مِنْ أَنْ يَكُونَ لَكَ حُمْرُ النَّعَمِ ‏"‏‏.‏