فَكَانَ ابْنُ عَبَّاسٍ إِذَا حَدَّثَ قَالَ: إِذَا سَمِعْتُمُونِي أُحَدِّثُ عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ، فَلَمْ تَجِدُوهُ فِي كِتَابِ اللَّهِ، أَوْ حَسَنًا عِنْدَ النَّاسِ، فَاعْلَمُوا أَنِّي قَدْ كَذَبْتُ عَلَيْهِ . .
Whenever Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated a hadith, he would say: When you hear me narrate a hadith of the Messenger, and you do not find it in the Book of Allah, nor do you find anything better with the people, then know that I have lied about the Prophet (peace be upon him).