Sahih Muslim
The Book on Government (Kitab Al-Imara)
Book Number: 020 / Hadith Number: 4669
The above tradition has been narrated on the authority of Khalid al- Juhani who said: The Prophet of Allah (may peace be upon him) said: He who equips a warrior in the way of Allah (is like one who dctually fights) aud he who looks after the family of a warrior in the way of Allah in fact participated in the battle.