Sahih Bukhari Volume 3, Book 26, Hadith 1783

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَحْيَى، عَنِ ابْنِ جُرَيْجٍ، عَنْ عَطَاءٍ، قَالَ سَمِعْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ يُخْبِرُنَا يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لاِمْرَأَةٍ مِنَ الأَنْصَارِ سَمَّاهَا ابْنُ عَبَّاسٍ، فَنَسِيتُ اسْمَهَا ‏"‏ مَا مَنَعَكِ أَنْ تَحُجِّي مَعَنَا ‏"‏‏.‏ قَالَتْ كَانَ لَنَا نَاضِحٌ فَرَكِبَهُ أَبُو فُلاَنٍ وَابْنُهُ ـ لِزَوْجِهَا وَابْنِهَا ـ وَتَرَكَ نَاضِحًا نَنْضَحُ عَلَيْهِ قَالَ ‏"‏ فَإِذَا كَانَ رَمَضَانُ اعْتَمِرِي فِيهِ فَإِنَّ عُمْرَةً فِي رَمَضَانَ حَجَّةٌ ‏"‏‏.‏ أَوْ نَحْوًا مِمَّا قَالَ‏

Narrated By Ata : I heard Ibn 'Abbas saying, "Allah's Apostle 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."