Abu Huraira (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "By Him in Whose hand is my soul! If I did not fear hardship for the believers, I would never stay behind from any expedition (military campaign) set out in the way of Allah. But (at this time) I do not have enough means, nor do they (i.e., the Companions) have the strength to go out with me, and their hearts do not accept that they remain behind me." And Ibn Abi Al-Zinad (may Allah have mercy on him) said at the end of the narration: "Khilaf Sariyyah" (i.e., staying behind from any expedition was against nature and desire).