Kings are ordained by God, and established by the people, to procure and provide for the good of those who are committed unto them, and that this good or profit be principally expressed in two things, to wit, in the administration of justice to their subjects, and in the managing of armies for the repulsing their enemies: certainly, we must infer and conclude from this, that the prince who applied himself to nothing but his peculiar profits and pleasures, or to those ends which most readily conduce thereunto, who contemns and perverts all laws, who uses his subjects more cruelly than the barbarous enemy would do, he may truly and really be called a tyrant, and that those who in this manner govern their kingdoms, be they of never so large an extent, are more properly unjust pillagers and free-booters, than lawful governors.

Vindicae Contra Tyrranos