La justicia, según Domingo de Soto, co-fundador de la Escuela de Salamanca, es el eje que vincula ley y derecho, los dos núcleos de su De iustitia et iure. Y la justicia, cuyo tratamiento último lo proporciona la filosofía y la teología, es una virtud humana que busca la justa relación de dos elementos, y que tiene por objeto la equidad, que se mide no tanto por la intención del agente, sino por su contenido objetivo. Lo justo se mide por dos planos, el del presupuesto y la consecuencia a los que se corresponden la ley y el derecho, con una estructura teleológica.

Justice, according to Domingo de Soto, co-founder of the School of Salamanca, is the axis that links the law with what is right, concepts that form the two cores of his Deiustitia et iure. Justice, whose ultimate justification is provided by philosophy and theology, is a human virtue which seeks the proper relationship of two elements, and which strives to achieve equity, which is measured not by the agent's intention, but by its objective content. What is just is measured along two planes, that of the premise and that of the consequences, which correspond respectively to the law, and to what is right.