is not a matter of eating and drinking
This phrase addresses the specific context of disputes in the early church regarding dietary laws and practices. The Greek words for "eating" (brosis) and "drinking" (posis) highlight the physical acts that were causing division among believers. Historically, Jewish dietary laws were a significant part of religious identity, and early Christians struggled with how these laws applied to them. Paul clarifies that the kingdom of God is not about adhering to these external rituals or practices. Instead, it is about internal transformation and spiritual priorities.

but of righteousness
"Righteousness" (dikaiosyne in Greek) refers to the state of being right with God, a central theme in Paul's writings. It is not achieved through human effort or adherence to the law but is a gift from God through faith in Jesus Christ. This righteousness is both imputed, meaning believers are declared righteous through Christ, and imparted, meaning it is lived out in daily life. The historical context of the Roman church, with its mix of Jewish and Gentile believers, underscores the importance of understanding righteousness as a unifying factor, transcending cultural and religious differences.

peace
The Greek word for "peace" is "eirene," which encompasses more than the absence of conflict. It signifies a holistic sense of well-being, harmony, and reconciliation with God and others. In the historical context of the early church, peace was essential for maintaining unity among diverse believers. Scripturally, peace is a fruit of the Spirit (Galatians 5:22) and a hallmark of the kingdom of God. It reflects the peace that Christ has made between God and humanity through His sacrifice.

and joy
"Joy" (chara in Greek) is a deep-seated gladness that comes from knowing and being in relationship with God. It is not dependent on external circumstances but is a result of the Holy Spirit's work within believers. Historically, joy was a distinguishing mark of the early Christian community, even in the face of persecution and hardship. Scripturally, joy is also a fruit of the Spirit and is closely linked with hope and faith.

in the Holy Spirit
This phrase emphasizes the source and power behind the righteousness, peace, and joy that characterize the kingdom of God. The Holy Spirit, or "Pneuma Hagion" in Greek, is the third person of the Trinity, actively working in the lives of believers to produce these qualities. The historical context of the early church highlights the transformative role of the Holy Spirit in guiding, empowering, and uniting believers. Scripturally, the Holy Spirit is the agent of regeneration and sanctification, enabling believers to live out the realities of God's kingdom in their daily lives.

Righteousness, and peace, and joy in the Holy Ghost.--By "righteousness and peace" is not here meant imputed righteousness, or justification and reconciliation with God, but rather the moral condition of righteousness in the Christian himself, and concord with his fellow-men. These are crowned in the confirmed Christian by that feeling of subdued and chastened exultation which is wrought in Him by the presence in his heart or constant influence of the Holy Spirit.

It is remarkable how, with all the wide difference in terminology between the writings of St. Paul and the Gospels, they yet come round to the very same point. The "kingdom of God," as here described, is exactly what we should gather from the fuller and more detailed sayings of our Lord. "Not that which goeth into the mouth defileth a man;" "The kingdom of God is within you;" "The kingdom of God cometh not with observation;" "If thine eye be single, thy whole body shall be full of light;" "Blessed are they which do hunger and thirst after righteousness;" "Blessed are the peacemakers;" "Rejoice and be exceeding glad."

It has not been beyond the power of heathen or even Christian philosophers, such, e.g., as Marcus Aurelius, to arrive at the conception of righteousness and peaceableness as duties to be observed and striven after. The peculiarity of Christianity consists in the unity which it gives to these attributes as naturally flowing from a spring of deep religious emotion, and from the finish and perfection which it adds to them by the introduction of that third term, "joy in the Holy Ghost." Many individuals have shown, and still show, with greater or less approximation, what the Christian type should be, but the great and only perfect Exemplar is Jesus Himself, and that less, perhaps, in the later portion of His career, when He was fulfilling that other side of His mission, to "bear the sins of many" as the Saviour of mankind, than in the earlier untroubled phase which finds expression in the Sermon on the Mount. This is in closest contact with the normal life of men.