 You kill yourself spiritually when you commit a mortal sin. Therefore, the way to remain in God's kindness is to remain in the state of grace. And if you should fall into mortal sin, and even in addition, the venial sins that you may commit, that we all commit, pray for forgiveness, go to the sacrament of confession when necessary, and then you're restored to the state of grace. That's what he's referring to there is remaining in the state of God's kindness, the state of grace.