Since God’s teaching is good and salutary, it should not be blasphemed, because of something trivial. Yet it is blasphemed when doubts are cast on the goodness of God’s creation. Commentary on Paul’s Epistles.
"Let not, then, your good be evil spoken of; for the kingdom of God is not meat and drink "says the apostle, in order that the meal spoken of may not be conceived as ephemeral, "but righteousness, and peace, and joy in the Holy Spirit."
Let not then our good, or which we have a Christian liberty to do with a good conscience, be evil spoken of, because of the disputes and quarrels you have about it. (Witham)
By “what is good to you” Paul means either their faith, or the hope of reward in the hereafter, or the perfection of their religious state. For it is not just that you fail to do anything to help your brother, Paul says, but you even cause the doctrine itself, the grace of God and his gift, to be spoken evil of.
