The homily I heard this morning drew a subtle point out of the story of Naaman the leper: the slaves and servants had more faith than the king and the general.
The homilist suggested this might be because slaves and servants, those with no standing in society, have no standing to lose by confessing faith in God.
Since I was (for some reason) already thinking about human and Divine will, I suggested to myself (and now to you) that it might be because slaves and servants, whose will in temporal matters is largely bound by their masters, make more use than their masters of their freedom of will in spiritual matters.
Created out of love, created in order to love, if a person finds that circumstances make it hard to love himself -- that is, to act for his own good -- he may also find they make it easy to love God. We are designed to love, not merely in terms of desire (I want the good) but in terms of effectiveness (I have obtained the good I wanted). A slave's self-love is less effective than his master's, so perhaps as a result his love of God is more effective.