al-Baqarah
The Messenger of Allah (pbuh) is quoted by Ubayy saying,
"Whoever recites it will receive blessings from Allah and His mercy and
will be granted the rewards due to one who camps for a full year, in the way of
Allah, as a soldier on the borders of the Islamic domains to protect them,
being constantly on vigil." Then the Messenger of Allah (pbuh) turned to
the narrator, Ubayy, and said, "O Ubayy! Order the Muslims to learn it,
for learning it is a blessing, while leaving it is a loss, and no magician can
ever overpower it."
He (pbuh) is also quoted as saying that everything has a zenith, and the zenith
of the Our'an is Surat al-Baqarah. "Which ayat (verse)," he
(pbuh) was asked, "in it is the best, O Messenger of Allah?" He
(pbuh) said, "Ayat al-Kursi [2:255]," he (pbuh) answered. And
he (pbuh) entrusted the youngest among his companions, namely al-Harith ibn
Zayd ibn al-Harithah, due to the fact that he knew Surat al-Baqarah by
heart, to command an army to defend Islam.