How do we live the Christian life in the day to day reality of sin, struggle and suffering? We can only do so by the power of the Spirit of God. With His help, we can put sin to death. With His help, we can live in a way that pleases God. With His help, we can endure through trials and suffering.
If we want to know how to live the Christian life, then we need to know what it means to live life in the Spirit.