Life's Wager is a hedge or counterbet to Pascal's Wager. Pascal's Wager states that just in case God does exist, we should worship God in order to get into heaven and to avoid hell in the afterlife.
By contrast, Life's Wager says: Just in case God and the afterlife do not exist, we should make sure our life still has meaning by striving to improve a different kind of afterlife, namely the lives of those who live on after us.
Even though Life's Wager takes an opposite position to Pascal's Wager, the two are compatible because one can practice both of them at the same time. Life's Wager highlights an alternative idea of afterlife that can give great meaning to life, while also providing a reason for moral behavior, even if religion is not in the picture.