It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) used to recite «﴿قُولُواآمَنَّابِاللّٰهِوَمَاأُنْزِلَإِلَيْنَاوَمَاأُنْزِلَإِلَىإِبْرَاهِيمَ﴾ [البقرة : 136]» till the last verse in the first rak'ah of Fajr, and in the second rak'ah he used to recite «﴿آمَنَّابِاللّٰهِوَاشْهَدْبِأَنَّامُسْلِمُونَ﴾ [آل عمران : 52]».
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 2038