The significance of religious faith to public life has quite been a topical issue within the last two decades. Scholars on the development and public life debate have argued for the presence of religious voices in public circles. This article discusses the basis of Christian-Muslim involvement in the public space. At the heart of such involvement is the Christian or Muslim who is both a religious person and a citizen of the state. Having looked at the notions from Christian-Muslim perspectives, the article shows that the public sphere is no prerogative of politicians or celebrities. The public space encapsulates every member of society, hence their involvement of which has profound ramifications for the notion of the Common Good, equitable solutions to collective problems, boundaries of inclusion and exclusion, and those practices that converge in the public. The study reflected on the case of Ghana and on why the Ghanaian Christian and Muslim must be involved in the Ghana‟s public life. The study demonstrates that religious faith in the public sphere remains indispensable for the preservation of the Common Good and hence makes the call for all religious people and people of good will, especially Christians and Muslims in Ghana to work in favor of maintaining the public sphere by being agents of the Common Good in that sphere.