The Khazar king's response to the diplomatic mission parallels the Israelites' response to the unanticipated mission and extraordinary benefits they received.
It is only after the king has expressed himself in this way that the sage begins to suggest that the entire thought experiment is parabolical and that the king has, in effect, endorsed the rationality and appropriateness of the sage's opening remarks. The endorsement was in his having responded to the unanticipated diplomatic mission to his court with all its concomitant benefits just as the biblical Israelites responded to the unanticipated mission and extraordinary benefits that came their way