He will be a servant to other servants. Without humility, however, the "servant" will become vain and proud; his vision of truth will likely become distorted by hubris. He will be no good to himself or to others. He will fight with other warrior-kings but for power and influence rather than for truth, beauty and goodness. Humility, in a sense, will keep him honest and in the light (even while laboring in the cave of darkness). As Plato says, it is the business of the Founders of the State to urge those citizens who are capable of learning towards the light of truth, that they may later labor alongside one another amongst the prisoners, accepting...

In this manner, Plato means to effect happiness in the whole State. Education benefits those who partake of it, and those who partake of it may then in turn benefit the State by helping those who have no education (520a). Thus, the role of the philosopher is inextricably linked to the role of the agent of socio-political change: both must strive towards the good and the beautiful, for themselves and for the Republic.
Works Cited

Plato. The Republic. (translated by G.M.A. Grube, revised by C.D.C Reeve).

Indianopolis, IN: Hackett Publishing, 1992. Print.