Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates from Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) that he said: "Indeed, the part of the Qur'an that was revealed last is this saying of Allah Almighty: "There has certainly come to you a Messenger from among yourselves. Grievous to him is what you suffer; he is deeply concerned for you, and to the believers he is kind and merciful" [Surah al-Tawbah: 128]."
This chain is hasan (good). Imam Waki' also narrated a similar narration from Imam Shu'bah with the same chain, and Ahmad bin Mani' narrated a narration with the same meaning through Hushaym from Mansur, from Imam al-Hasan al-Basri, from Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him).
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب التفسير / 3617
Hadith Gradingمحدثین:إسناده حسن
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :قال ابن حجر: هَذَا إِسْنَادٌ حَسَنٌ » «أخرجه مسند أحمد برقم: 20720، وأخرجه فتح الباري برقم: 6319، وأخرجه مجمع الزوائد ومنبع الفوائد برقم: 11062»