Aali-'Imran
The Messenger of Allah (pbuh) is quoted as saying that one who recites it will be given for each of its verses security on the bridge over hell, and whoever recites it on Friday will be blessed by Allah and His angels all day long till sunset. He (pbuh) is also quoted saying, "Memorize Surat al-Baqarah and Surat Aali' Imran, for they are like two fragrant flowers, and they will shade the one who learns them by heart on the Day of Judgment like two douds..." to shade those who used to recite them quite often from the intense heat of that Day.