If you ask Roman catholic believers what it is that makes the church distinctive, they will probably begin speaking of the sacramental hierarchy by which the whole church is ordered and held together. Put the same question to contemporary Protestant theologians, and they will start telling you about 'practices,' those communal behaviors by which the church marks itself out as an alternative social order. But if you ask a Russian Orthodox believer what makes the church distinctive, she will think at once of holy lives: when she says the word 'church,' it is not the face of the bishop that comes to mind, nor merely her own face, but the faces of the saints.
Why are all the walls of Russian churches so crowded and cluttered with icons of the saints? It is not because the Orthodox love pictures, but because they love light. For the icons are not art works, but windows: they are the small openings through which the light of God bursts in upon the gathered church. It is here, in the lives and prayers of the saints, that the church is irradiated and sustained. The saints have lived in such proximity to God that they become a kind of intercession for the rest of us. God looks at us through them: they are God's windows.
-- Ben Myers, Christ the Stranger