an implication of the law of sympathy is that the meaning that associates two things establishes a connection between them. and spiritual power can flow down that connection from one thing to another.
an example: a drawn symbol represents fire, its meaning evokes the flame in some specific way. that meaning establishes a connection between the drawn symbol and the element of fire, and the spiritual power of the flame can be drawn on through that drawn glyph.
association is about how two things, be they physical things or abstract ideas, are connected. the connection itself is through resemblance, and that connection allows the spiritual essence and powers of one thing to be channeled and utilized through its associated partners.
resemblance/meaning/association forges a connection, the connection opens the path for power to flow, the power makes the magic go.