The first response about the mulberry tree is strange given Jesus’ own refusal to engage in demonstrations of power (Luke 4:1-12). Trees simply don’t transplant themselves on demand. Would they do so if we believed it possible? I think not. So what is going on here?
Jesus often uses hyperbole to make a point. He seems to be asserting the power of faith to ‘save’ as he did when some faith-filled people brought their paralysed friend to him for a cure, or when the centurion appealed to him on behalf of his dying slave, or when the woman massaged his feet with perfumed oil. It was faith that ‘saved’ them. This time he uses metaphorical language to the same end. In effect he is saying that even the faintest glimmer of faith has the most extraordinary effects. Later in Luke’s gospel, Jesus will contrast those who have faith with those who ‘ trust in themselves that they are righteous and regard others with contempt’ (18:9).
The slave story provides some interesting, even disturbing insights into the institution of slavery in the world of first century. Slaves have no expectation of sustenance when they come in from a hard day’s work. They attend first to the master’s needs, and even then they deserve no recognition or credit. This is simply how it is for slaves. Note that ‘worthless’ is a misleading translation of the Greek achreiai: slaves are in fact extremely valuable to their owners, even if nobody actually owes them anything. How can undeserving slaves provide a prototype for gospel leadership? How does this image fit with the supposedly inclusive vision of the gospel as a whole?
Our church tradition has always distinguished between those elements in the text that are situation-bound and those that have enduring significance. We need the wisdom to discern the latter and the insight to refuse to re-inscribe oppressive first century societal practices.
The story invites us to have faith and to do what we ought to do without looking for undue recognition. As for claiming the status of ‘slaves’, that can have little if any value in our times.