It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "After the conquest of Makkah, migration is no longer obligatory, but jihad and intention remain. Therefore, when you are called to go out for jihad, then you should go out."
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 1991