Abstract: This paper examines the importance of comparative method in today’s ecclesiological reflection. The appearance of ‘historical-comparative ecclesiology’ in Roger Haight’s recent writings on ecclesiology counters the prevailing belief among many in the ecumenical circle that comparative ecclesiology has met its end in the Lund’s (Sweden) Faith and Order Conference (15-28 August 1952). Haight’s version of comparative ecclesiology takes a step forward from Lund by creating a space for the churches to learn and embrace the common ground of human existence, which is no other than the God revealed in Jesus. Karl Rahner’s theology of grace is expounded in this paper to support the claim that the foundation of comparative ecclesiology is inherent in the very human and divine exchange. It is, likewise, argued that comparative ecclesiology is a ‘learning ecclesiology,’ which makes ‘love’ as both its source and aim.