What does Deuteronomy 15:18 mean?

Don't feel bad about setting your servant free after six years. They've worked for you for six years, worth twice what you'd pay a hired worker, and the Lord your God will bless you in everything you do. Deuteronomy 15:18 - Modern Text Bible

(Letting a servant go free isn't a loss—it's right and fair. God will bless you for treating people well.)