Rhetoric: Benjamin is building a logical case. Beginning with the incontrovertible evidence of his work in service of his people, Benjamin is creating an analogy between that known past and the new covenant he will propose, moving from the physical to the spiritual, from the tangible earthly king to the spiritual celestial king. In that covenant, the people must accept a new or renewed relationship with Yahweh. Verse 18 expands the theme of service introduced in verse 17, stressing that it is an achievable goal. If Benjamin can serve them, surely they can serve one another. Benjamin is not asking them to do anything that he has not already done, a fact they themselves have witnessed (v. 14).
Benjamin has begun by describing the master’s perspective—specifying what is required of the servant. Now he examines how the servant should view the master. The people are grateful to Benjamin for his services and also for his freeing them from burdens “grievous to be born.” Yet Benjamin is the servant of the heavenly king. Thus, the people should in reality be expressing thanks to the heavenly king—Benjamin’s master. Rather than building a society in which the earthly king is the master, Benjamin is focusing the people’s gratitude and service on the heavenly king.