The Messenger of Allah ﷺ said, "Ramadan has come. During it, the gates of Paradise are opened, the gates of Hell are closed, and the devils are chained."
حدثنا يعقوب حدثنا أبي عن ابن إسحاق قال ذكر الزهري عن أويس بن أبي أويس
أن رسول الله ﷺ قال هذا رمضان قد جاء تفتح فيه أبواب الجنة وتغلق فيه أبواب النار وتسلسل فيه الشياطين
Its isnad is sahih. Yaqub is Ibn Ibrahim bin Saad Zuhri, who is trustworthy, as is his father. Ibn Ishaq is Muhammad, the leading authority on military campaigns, and he practices tadlis, but he stated explicitly that he heard directly from Zuhri many times. Uways bin Malik was an ally of Banu Tamim, whom Ibn Hibban deemed trustworthy, and Ahmad did not criticize him.The hadith was reported by Nasai, 4/128, number 2103, in the chapter on fasting.