Paul often called himself a slave of Jesus (see Rom. 1:1 for one such example). Unfortunately, thanks to the blot on American history known as slavery, we often have trouble with this concept, which explains why most translations prefer to use words like “servant” or “bond-servant.” Such words a perfectly acceptable. It is unfortunate, however, that none of them quite catch the nuance found in the word the NT writers used. If “slave” brings to mind plantation work, “servant” brings to mind butlers and maids, which is certainly not the picture the Bible intends to paint.
The Greek word for “slave” is doulos. A doulos was one who was in the service of another who was called his master (kurios). There were several words used to describe this relationship, one of them being the word from which we get our word “deacon.” Doulos‘ emphasis, though, is on the slave’s relationship to his master. That relationship is two-fold. First, it is one of absolute dependence, and second, it is one in which even the will under subjugation.
Because of this absolute dependence (even of the will), the Greek world despised slaves. For them, to be human was, essentially, to be free. Thus, to become a slave was to become in some way less than human. This is so true that they did not even consider themselves “slaves” of their gods! Each man was free unto himself. For this reason, the idea of slavery was a completely secular concept. It rarely appears in their religious literature.
The Hebrew concept–in fact, the entire oriental concept–of slavery was similar with one exception. Slavery was still viewed as absolute subjugation to another, both mind and body, but it came to acquire religious significance as well since men were the slaves of their kings (cf. 1 Sam. 17:58). It is only a short step to consider all men servants of the King of Kings (Ps. 27:9, etc.).
Understanding this basic concept helps us more clearly see the importance of Christians as “slaves” of God and Christ. We are absolutely dependent on Him for everything, including our very being. As such, He exercises complete sovereignty over us, which demands that He claims the right even to our wills. Put differently, our singular will should be to do the will of God.
To take one example, Jesus said in Matt. 6:24 that no once could serve (douleuein, from which we get doulos, “to serve”) two masters. The reason is now obvious enough. I cannot be completely dependent on two things. If I am completely dependent on one, I cannot be partially dependent on another. Further, if both demand complete obedience of my will, then when their wills conflict, I must choose one of the two, in which case, I am no longer the doulos of one. As Jesus says, I will love one and hate the other. In this, we see the full nature of God’s call. If we are His slaves, then any degree of self-dependence is sin in that it denies God’s claim over us.
In a culture committed to radical individualism such as our own, such a message is offensive. It was in Paul’s day, too. That is why he pointed out that no one is really free. If we are not God’s slaves, then we are slaves to sin (Rom. 6:16). Satan’s lie in the garden was far deeper than Eve could have ever understood. Yes, she became like God in that she knew good and evil, but only God serves no one. When they fell into sin, they simply stopped serving a loving master and began serving a cruel one. The same choice applies to each and every person today, especially Christians. Who will you serve? Whose doulos will you be?