Sahih al-Bukhari 4654
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · Allah's Statement: "Freedom from (all) obligations (is declared) from Allah and His Messenger ﷺ to those of the Mushrikin [polytheists, pagans, idolaters, disbelievers in the Oneness of Allah and in His Messenger Muhammad ﷺ] with whom you made a treaty." (V.9:1)
Narrated Al-Bara:
حَدَّثَنَا أَبُو الْوَلِيدِ ، حَدَّثَنَا شُعْبَةُ ، عَنْ أَبِي إِسْحَاقَ ، قَالَ سَمِعْتُ الْبَرَاءَ ـ رضى الله عنه ـ يَقُولُ آخِرُ آيَةٍ نَزَلَتْ {يَسْتَفْتُونَكَ قُلِ اللَّهُ يُفْتِيكُمْ فِي الْكَلاَلَةِ} وَآخِرُ سُورَةٍ نَزَلَتْ بَرَاءَةٌ.
The last Verse that was revealed was: 'They ask you for a legal verdict: Say: Allah directs (thus) about Al-Kalalah (those who leave no descendants or ascendants as heirs).' And the last Sura which was revealed was Baraatun (9) .