"One person went to the Prophet (SA) and said: 'I have a wife who always welcomes me when I come home, and escorts me to the door when I leave. When she finds me sad and unhappy, she then, by consoling me says: 'If you are thinking of sustenance, then do not despair, because Allah provides sustenance; and if you are thinking about the next life, then may Allah increase your intellect and efforts. Then the Prophet (SA) stated: ' Allah surely has functionaries and agents in this world and your wife is one of those. Such a woman would be rewarded half as much as a martyr'."
http://al-islam.org/marriageandfamily/