Sahih Muslim Book 20, Hadith Number 4665.

Chapter : The merit of helping the warrior (fighting in the way of Allah) with something to ride upon and looking after his family in his absence.

It has been narrated on the authority of Abu Mas’ud al-Ansari who said: A man came to the Messenger of Allah (may peace be upon him) and said: My riding beast has been killed, so give me some animal to ride upon. He (the Holy Prophet) said: I have none with me. A man said: Messenger of Allah, I can guide him to one who will provide him with a riding beast. The Messenger of Allah (may peace be upon him) said: One who guides to something good has a reward similar to that of its doer.