Romans 1:1 — Paul, a servant of Jesus Christ, called to be an apostle, separated unto the gospel of God.
The Greek word translated “servant” is actually the word for bondservant. In the Law of Moses, there was provision for someone who was in debt and could not pay. He became the property — the slave — of his creditor. But every seven years, all slaves were to be released, their debt wiped out.
But there were slaves who realized that they were much better off under their masters than they would be on their own. They were aware of the very-real possibility that their freedom would only lead to more debt, perhaps under a less kind master. A slave in this position had the option of choosing to become a permanent slave — a bond slave. He would be taken to the tabernacle where a priest would stand him up against a doorpost and knock a hole in his hear with an awl. His slavery was now permanent. It was a voluntary submission.
This is the title Paul uses to identify himself — a voluntary slave of Jesus Christ.
The order of the titles Jesus Christ and Christ Jesus is always significant: “Christ Jesus” describes the One who was with the Father in eternal glory, and who came to earth, becoming Incarnate; “Jesus Christ” describes Him as the One who humbled Himself, who was despised and rejected, and endured the cross, but who was afterwards exalted and glorified. “Christ Jesus” testifies to His pre-existence; “Jesus Christ” to His resurrection and exaltation. (The Epistle to the Romans, by W. E. Vine (Oliphants Limited), 1948.)