Pattern users are faced with difficulties in understanding when and how to use the increasing number of available design patterns. This is mainly due to the inherent ambiguity in the existing means (textual and graphical) of describing them. Hence, there is a need to introduce formalism in order to describe them accurately and allow rigorous reasoning about them. The main problem of existing formal specification languages for design patterns is their lack of completeness. This is mainly because they tend to focus on specifying either the structural or the behavioral aspect of design patterns but not both of them. We propose a simple yet Balanced Pattern Specification Language (BPSL) that is aimed to achieve equilibrium by specifying both aspects of design patterns. BPSL combines two subsets of logic, one from First Order Logic (FOL) and one from Temporal Logic of Actions (TLA).