Paul has prayed for the unity and harmony of the church in Rome. Now he instructs them one more time to welcome each other as Christ has welcomed them. This is not merely a nice-sounding phrase to tack on the wall. Paul is commanding believers to fully accept and include other Christians in community with themselves, including those who disagree strongly about what is and is not permitted (Romans 14:1–2; 14:20–21). He is commanding them to set their Christ-won freedoms aside, if necessary, to build up the church (Romans 14:13).
Why would they do this? In the end, it is all to add to God’s glory. Put negatively, a refusal to welcome Christians who disagree with my convictions will keep me from participating in bringing glory to God. It will keep me from achieving the very purpose of my life. Acting as if my own convictions are beyond doubt—as if I were infallible or beyond reproach—makes it difficult for me to appreciate God’s holiness and majesty, let alone my own role in the body of Christ.
Romans 15:1–7 concludes Paul’s teaching on how Christians with strong faith, those who understand their freedom from the law, should live with those of weaker faith. All Christians must please each other and not themselves. After all, Christ didn’t come to please Himself. With God’s help and encouragement, everyone in the church can live together in harmony and glorify God with one, unified voice, as they serve each other ahead of themselves. They must welcome each other as Christ has welcomed them.