4:1-9 It’s God’s will that we become holy -- being saved by grace made us holy positionally, but God also wants us to become holy actually. So we need to discipline ourselves to eschew lustful passions. In contrast to lustful passions, we must practice brotherly love.
4:13-18 Death should be no terror for Christians, because we have the hope of resurrection. Jesus's death and resurrection is the promise of our own.