Which two Surahs are known as "Al-Zahrawayn"?

The two surahs are Al-Baqarah and Al 'Imran, and they were named Al-Zahrawayn (the two luminous ones) because the Prophet (peace and blessings be upon him) said: "Recite the two luminous ones, Surat Al-Baqarah and Surat Al 'Imran, for they will come on the Day of Resurrection as if they were two clouds, or two canopies, or two flocks of birds in ranks, arguing on behalf of their reciters." They were named thus due to their light, guidance, and immense reward.