Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) said: The last verse revealed to the Prophet (peace and blessings be upon him) was: "There has certainly come to you a Messenger from among yourselves" [Surah al-Tawbah: 128], to the end of the verse.
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 530