For the kingdom of God is not a matter of eating and drinking but of righteousness and peace and joy in the Holy Spirit. Paul sweeps away externals: God's kingdom does not consist of rules about eating and drinking but of what the Spirit produces, righteousness, peace, joy.
Righteousness is not a goal you achieve, it is a component of the kingdom you live in. It is a gift, not homework. And peace and joy come with it, not as reward but as natural fruit of your standing.