What does Smith mean by a "natural" order of a society and with what does he contrast this order?

Chapter two implies the idea that people are motivated primarily by their own self-interest. Self-interest, for Smith, does not have many of the negative connotations that it does today. Instead, Smith means to make the point that it is entirely natural, appropriate, and indeed necessary for society that each person look after his own welfare, and not put the burden of his maintenance upon others. It is this propensity that allows human economies, left largely to themselves, to thrive as if it were in their very nature to do so.