Abu Dawud
Jihad
Book Number: 008 / Hadith Number: 2496
Narated By AbuUmamah : The Prophet (pbuh) said: He who does not join the warlike expedition (jihad), or equip, or looks well after a warrior's family when he is away, will be smitten by Allah with a sudden calamity. Yazid ibn Abdu Rabbihi said in his tradition: 'before the Day of Resurrection".