It is often argued that religions do not take earthly life - and with that inequalities and concrete peacebuilding - seriously, but rather encourage people to look beyond it toward salvation and rewards in the afterlife. After having shown the challenges in defining the keywords "fraternity", "world peace" and "inequalities", this paper will retrace some major steps in the last decades that will contradict this popular feeling. We will do that through an analysis of Catholic Church documents going from the Second Vatican Council until the Document on Human Fraternity and then the beginning of the Pontificate of Pope Leo XIV. A theology of peace built upon the theological category of fraternity will thus be delineated as a concrete way to address inequalities but also as a spiritual practice that opens for a deeper transcendental experience.