The Messenger of Allah ﷺ said, "An Umrah performed in Ramadan equals a Hajj."
حدثنا زكريا بن عدي أنبأنا عبيد الله يعني ابن عمرو الرقي عن عبد الكريم عن عطاء
قال رسول الله ﷺ عمرة في رمضان تعدل حجة
Its isnad is sahih. Ubaydullah bin Amr Raqqi, Abu Wahb, is trustworthy, and Abdul-Kareem is Ibn Malik Jazari, who is also trustworthy, and both have been mentioned before. Tirmidhi related the hadith, 2/267, no. 939, in Hajj, what has been said about umrah in Ramadan, and he said, hasan gharib. Darimi related it, 2/73, no. 1860, and Ibn Majah, 2/997, no. 2995.