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Ibn 'Abbas reported that the Messenger of Allah (ﷺ) used to recite in the two (supererogatory) rak'ahs of the dawn prayer:" Say: We believed in Allah and what was revealed to us" and that which is found in Surah Al-i-'lmran:" Come to that word (creed) which is common between you and us" (iii. 64).
Source: sunnah.com
Other translations
Arabic
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو خَالِدٍ الأَحْمَرُ، عَنْ عُثْمَانَ بْنِ حَكِيمٍ، عَنْ سَعِيدِ بْنِ يَسَارٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَقْرَأُ فِي رَكْعَتَىِ الْفَجْرِ { قُولُوا آمَنَّا بِاللَّهِ وَمَا أُنْزِلَ إِلَيْنَا} وَالَّتِي فِي آلِ عِمْرَانَ { تَعَالَوْا إِلَى كَلِمَةٍ سَوَاءٍ بَيْنَنَا وَبَيْنَكُمْ}
sunnah.com