Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
حَدَّثَنِي عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ، حَدَّثَنَا سُفْيَانُ، عَنْ عُبَيْدِ اللَّهِ، قَالَ سَمِعْتُ ابْنَ عَبَّاسٍ، قَالَ كُنْتُ أَنَا وَأُمِّي، مِنَ الْمُسْتَضْعَفِينَ.Narrated Ibn `Abbas:My mother and I were among the weak and oppressed (Muslims at Mecca)
From Sahih al-Bukhari, whose reports the scholars accept as authentic.