http://www.orthodox.net/articles/against-ecumenism.html

If there is to be true spiritual unity, it must be within the one holy, catholic and apostolic Church: the Orthodox Church. While other religions weaken from attempting to please everybody and pass off theology as unimportant, Orthodoxy alone remains firm and unshaken, a rampart unyielding to the turmoil of the world, illustrating the way of the straight and narrow path. In Orthodoxy, we strive to conform our sinful human nature to the teachings and lifestyle of the Church, as opposed to the "suit-yourself" attitude many other religions have, in which people create their own set of beliefs that accommodate their lifestyle. Orthodoxy is that rock upon which Christ has built His Church. Let us cling to that holy rock and not allow for innovations to come into the Orthodox Church. We have been given so much in the Faith, and we must preserve it uncorrupted by modern practices and ways of thinking, such as minimalism and compromising our faith to the world. We must be in the world but not of the world, and this is done by remaining in the embrace of the Orthodox Church.