Chapter: Should it be said Ramadan or the month of Ramadan? And whoever thinks that both are permissible

Allah's Messenger (ﷺ) said, "When Ramadan begins, the gates of Paradise are opened."

Allah's Messenger (ﷺ) said, "When the month of Ramadan starts, the gates of the heaven are opened and the gates of Hell are closed and the devils are chained."

I heard Allah's Messenger (ﷺ) saying, "When you see the crescent (of the month of Ramadan), start fasting, and when you see the crescent (of the month of Shawwal), stop fasting; and if the sky is overcast (and you can't see it) then regard the month of Ramadan as of 30 days."