Here then are the 5 reasons that we do good works with their associated texts:
1) We do good works to obey God, who we love. (1 John 5:3; 4:19)
2) We do good works because we love our neighbor. (Matthew 5:43-45; 22:36-40)
3) We do good works to show the world God’s character and God’s work. (Matthew 5:16; 5:13)
4) We do good works because they are the fruit of the Spirit’s work in us. (Matthew 7:16-20; Galatian 5:22-23; Ephesians 2:10; James 2:26; 2:21-25)
5) We do good works to win a hearing for the gospel.
Again, I would encourage to read the book.
One parting quote from that section of the book, “if we are Christians who’s love and compassion is aroused not just by physical and emotional needs, but also by spiritual needs, then showing the gospel will always be at the forefront of our minds. We will naturally and readily move toward it as we are loving other people.”