The Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), said: I asked the Prophet (peace and blessings be upon him) for permission to wage jihad, and he (peace and blessings be upon him) said: "Your jihad is your Hajj, or: performing Hajj alone is sufficient for you."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17802