Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates: A woman came to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) asked her: "What has kept you from Hajj?" She said: We had only one water-carrying camel, and my father and my husband have gone out on jihad on it. He (peace and blessings be upon him) said: "Perform Umrah in Ramadan, for it is equal to a Hajj for you."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12405