Statically bound SQL results in faster execution because the access plan is "pre-bound" to the DB2 system catalog. Dynamic SQL, on the other hand, is interpreted and bound at run time, and then executed.
Dynamic SQL is, by analogy, like compiling a program every time you want to use it.
On high volume, large systems, dynamic SQL is generally not recommended due to response time issues.
You can read more about Dynamic and Static SQL here.