At the beginning of his letter to the Romans, Paul introduces himself as “Paul, a slave of Christ Jesus, a called apostle set apart for the gospel of God ….”
One would think that this would be a rather difficult verse to misinterpret, but nearly anything is possible in biblical interpretation. In this case (as in many), archaic translation bears the brunt of the blame, as several translations render the Greek word for “slave” (δούλος, doulos) as “bondslave,” “bondservant,” or similar form that has fallen out of common use. In order to explain the unusual word, folks who don’t really know the original languages explained this difference by looking back to Exodus 21:6, which lays out the procedure for a debt slave to become a life-long slave (a decision presumably tied to a good master or perhaps a wife given to him by the master while under debt slavery), sealed by the piercing of the ear with an awl.
Anyway, the teaching in question basically explains that Paul wasn’t just a regular slave, that his use of the term “bondslave” (rather than “slave” or “servant”) refers to the voluntary slavery of Exodus 21, highlighting Paul’s piety or underscoring some difference between these concepts. The problem is that this notion results from those who not only don’t know the original languages but also don’t really know these somewhat archaic English words. Etymologically, “bond-servant” is used to distinguish a purchased slave who is owned by (bound to) his master from a servant who is simply hired help but is free to go elsewhere. Essentially, “bond-servant” means “slave,” in distinction from “servant”; another equivalent term often used before the 20th Century was “bondman” (i.e. “bound man” or “man of bondage”), which is what the Darby translation uses.
“Bond-slave” arises from the same origin and is a direct (albeit emphatic) synonym to “slave,” again meaning an owned or purchased slave, one bound to a master as opposed to a free person. These words aren’t used today outside of Christianese, which lends them to easier misunderstanding. The translations that use “bond-servant” are actually trying to distance themselves from the KJV, which simply uses “servant,” which isn’t really the right word to translate δοὐλος today, since “servant” in modern English implies a free person in distinction from a slave bound to an owner. But many translations are a bit twitchy about using the word “slave” in these cases due to the extremely negative connotation attached to this word today (thanks to our history of race-based slavery). Thus, some 20th Century translations elected to go with the somewhat archaic but more precise “bondservant” (NKJV & NASB) or “bondslave” (again the NASB, which isn’t consistent w/its rendering of this word).
This led to the fanciful interpretations going back to the “voluntary” slave of Exodus 21, explaining that this is why Paul would call himself a “bondslave” as opposed to just a “servant” or “slave.” Of course, it’s all completely wrong. Paul simply uses the basic Greek word for “slave.” There’s no inherent notion of volunteerism in this word—it’s the same word that was used for a slave that was purchased at a slave market or from another owner—nor is this a unique word, as the archaic translation “bondslave” might suggest. Rather, Paul merely uses the basic word for a person who is owned by another person.
For that matter, Exodus 21 doesn’t support this change in terms, either. The Hebrew word in the passage doesn’t change—the man is a “slave” (עבד) before his ear is pierced, and he serves (עבד) after his ear is pierced. Same word. If one wants to point out a difference, it is between a debt-slave in the first instance—an Israelite debt-slave could only be held for seven years—and a “slave” or “bond-slave” (that is, an owned slave, one in bondage—a much more severe state) in the latter state. “Bond-slavery” is the more severe enslavement—a permanent one in which one is owned as property, as opposed to debt-slavery, which was to be limited in its timeframe. Either way, by Paul’s day, the debt slavery outlined in Exodus 21 (and the practice of voluntary slavery) had long ceased; in his introduction, Paul was straightforwardly using the standard word for “slave.” It is extremely far-fetched to think of this as an intentional reference to Exodus 21, and it’s even more unlikely that his audience (who were accustomed to hearing δούλος in everyday speech) would have connected Paul’s self-identification as a slave to ancient Israelite slavery regulations.
There’s no question that Paul’s application of δοὐλος to himself indicates his being “bound for life” to serve God, and he uses the word denoting the most servile state one could have in the Graeco-Roman world: “slave.” But the point is better preserved by applying the modern form of the word in the passage, and any attempt to find something “special” about this particular word (beyond its indication of being owned and in a servile state) goes beyond the evidence of the text. It really does just say: “Paul, a slave of Christ Jesus.”