This is volume 8 in the “New Studies in Biblical Theology” series. These books take a single topic and trace it right through the Bible or New Testament. They are not typically light reading, but serve as very useful background material for those preparing for preaching or simply wanting to get some in-depth insight into major biblical themes. The subject here is that of the use of “slave of Christ” as a metaphor for total devotion to Christ.

One of the interesting issues this book raises is that modern Bible translators shy away from using the word ‘slave’ to translate doulos. This is undoubtedly due to the negative connotations that slavery carries, but Harris believes that we miss out on a true appreciation of the meaning by toning the terminology down to just “servant”, which loses the connotation of belonging.

The book begins with a fascinating survey of the nature of slavery in Roman, Greek and Jewish cultures of the first century. These, rather than the African slave trade of the 18th century form the conceptual background to the use of this term in the New Testament.

A slave may be defined as “someone whose person and service belong wholly to another”. Roman slavery law was complex, and up to a quarter of people were slaves in the Roman empire, doing a wide range of work. Surprisingly, most Roman slaves were able to gradually earn money, allowing themselves to buy their freedom through “manumission” by their 30s.

Harris explores whether the NT could be said to “endorse” slavery, since it lacks any explicit repudiation of it. It is true that the NT seems to accept it as the status quo, yet sees the gospel as being the means of the breakdown of the slave/free distinction. The NT is able to use slavery as a negative metaphor (such as bondage for sin), but also uses it in a positive sense to illustrate the humble way in which believers are to serve Christ. Paul strongly hints to Philemon that Onesiphorus should be freed, but refrains from commanding it. Harris suggests a variety of reasons why the NT lacks an explicit condemnation of slavery. Ultimately, the NT’s aim is first at personal transformation, which should then result in societal transformation.

Then follow four chapters exploring different aspects of slavery as used in the metaphor of slavery to Christ. First, freedom in the NT is presented as voluntary surrender to God’s will. The freedom we have in the gospel is not for license, but in order that we might be slaves to Christ. He shows how Paul in Rom 6:15-23 contrasts two slaveries. Everyone is either a slave to sin (Satan as master) or righteousness (Christ as master) – there is no third option. Christians need to beware the danger of temporarily reverting to slavery to sin.

Secondly, Harris shows how the whole concept of Christ as Lord depends heavily on the slave metaphor – where there is a slave there is a lord. A slaves duty was first to obey any explicit commands from their lord, and second, in the absence of such commands, to take actions that will please the master. The NT also expresses our obligations to serve one another through the slave metaphor.

Third, slavery connotes ownership. He sees water baptism “into” the name of Jesus, as representing a legal transfer of ownership. Harris explores several ways you could become a slave in Roman society and contrasts this with the way we become slaves of Christ.

Fourth, Harris addresses the suggestion of some that “slave of God” was actually intended as a title of privilege, i.e. applying only to very important Christian leaders such as Paul. Harris agrees that it is an honour to be a slave of such a great and gracious master, but argues that to be a slave of Christ (or of God) is a privilege for all believers, not just a few.

Harris claims that the concept of slavery to Christ is central to the NT concept of discipleship. Whilst the NT authors would be aware of the negative connotations of the slavery metaphor, the concept of slavery to Christ is presented as entirely positive – it represents our exclusive devotion to Christ, expressed in humble submission, unquestioning obedience and and exclusive preoccupation with pleasing him.

He then deals with two texts that might possibly be considered contradictions to the concept that a believer is the slave of Christ. The first is John 15:15 and the second Gal 4:7. He argues that these do not invalidate the metaphor of slavery to Christ, but rather define its boundaries and limitations. We are both sons and slaves.

A final chapter explores four case studies of characters in the NT demonstrating what it means to be a slave of Christ. These are Dorcas, Onesiphorus, Priscilla and Aquila. The book has three appendixes, the most interesting being the one where he explores the translation of doulos and calls on Bible translators to make more regular use of slave as its translation, particularly where slavery to Christ is in view.

Overall I would say this is a fascinating study on a theme that is regularly overlooked due to the reluctance of modern translators to use the term ‘slave’. It has certainly made me more aware when the term “servant” or “serve” comes up that there may be a root word of doulos underneath. There is however more to be explored on the relationship between the two metaphors of Christians as slaves of Christ and sons of God, though. Is one primary and the other secondary? Can they be held together easily? But apart from that unresolved issue I found this book very helpful. In particular, the metaphor of slavery sheds light on the exhortations to live with the ambition of pleasing the Lord.