Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated that the Messenger of Allah (peace and blessings be upon him) asked an Ansari woman (Umm Sinan), "Why did you not perform Hajj with us?" She replied, "We had only one camel, on which Abu Fulan (i.e., her husband) and his son rode off (for Hajj), and they left one camel behind which is used to bring water." The Prophet (peace and blessings be upon him) said, "Alright, when Ramadan comes, perform Umrah, for Umrah in Ramadan is equal to Hajj," or he said something similar to this.