This article strives to synthetically examine the topic of “envying others’ grace”, understood as a sin against the Holy Spirit. To understand the meaning and importance of this topic, some previous theological considerations are presented, followed by theological reflections supported by ecclesial tradition – with the special reference to Saint Thomas Aquinas. The conclusions we offer allow to acknowledge that this topic points out to –although vicariously the nature of Christian event and its reasoning, as well as to the nature of the ecclesial communion and its unity. Thus, this is a topic related to fundamental theology, which can receive useful insight from this reflection.