Nursing theory has been the cornerstone of the nursing profession dating back to the primitive days of Florence Nightingale. When examining the method of nursing theory formation, it is important to evaluate the core concepts of the theory. Core concepts surround a theory creating the basis for the theory or model. In nursing, concepts help in the development of theories and provide a pathway that will evolve over time and continue to provide competent and holistic nursing care. Theorists have developed different models or theories but, each theory/model may have common core concepts. This paper will identify and compare a core concept that is shared alike by two nursing theorists Virginia Henderson and Dorothea Orem. These theories will then be analyzed and compared and applied to the modern science of nursing to illustrate the practical use of these theories today.