This paper analyses the idea of the equality of the acquired moral virtues in Jan Gruzewski's (1580-1646) Ultima et maxima hominis mutatio (1641, 1644). Gruzewski, who was the rector of Vilnius University and a prominent Jesuit thinker, adopted the Thomistic distinction between acquired and infused moral virtues and understood the first group of virtues as the ones which are developed through the repeated practice of virtuous acts, while infused virtues were defined as the ones which are gifted by God and direct us towards our ultimate supernatural end. The idea of equality often emerges in various sociopolitical contexts in the first book of the treatise as Gruzewski was known for his tolerance for the political and religious opponents and encouraged to view the coexistence of the differing worldviews as beneficial for both the individual and the community. In the last chapters of the first book, Gruzewski analyses the concept of equality through the moral and logical lens and asks whether such acquired moral virtues as wisdom, justice, courage and temperance are equal to each other or whether we should assume some internal hierarchy between them. Gruzewski elaborates Aquinas' view that the answer to this question depends on the perspective from which acquired virtues are considered and claims that (1) all acquired virtues are equal in their dependence on reason and in their aim which is moral goodness, but (2) at the same time are unequal in that one is closer to reason than another, in the perfection of their respective objects, and in the realization in the individual. The aim of the paper is to show that although Gruzewski does not depart doctrinally from Aquinas, he puts a stronger emphasis on the practical orientation of the doctrine, encouraging moral growth and formation.