(4) باب عُمْرَةٍ فِي رَمَضَانَ
Narrated Ata:
I heard Ibn `Abbas saying, "Allah's Messenger (ﷺ) asked an Ansari woman (Ibn `Abbas named her but `Ata' forgot her name), 'What prevented you from performing Hajj with us?' She replied, 'We have a camel and the father of so-and-so and his son (i.e. her husband and her son) rode it and left one camel for us to use for irrigation.' He said (to her), 'Perform `Umra when Ramadan comes, for `Umra in Ramadan is equal to Hajj (in reward),' or said something similar."
Reference: Sahih al-Bukhari 1782
In-book reference: Book 26, Hadith 10
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 27, Hadith 10