88 But the danger remains. Indeed, the worker in the apostolate is under constant fire. The desire to come together as brothers must not lead to a watering down or whittling away of truth. Our dialogue must not weaken our attachment to our faith. Our apostolate must not make vague compromises concerning the principles which regulate and govern the profession of the Christian faith both in theory and in practice. An immoderate desire to make peace and sink differences at all costs (irenism and syncretism) is ultimately nothing more than skepticism about the power and content of the Word of God which we desire to preach. The effective apostle is the man who is completely faithful to Christ's teaching. He alone can remain unaffected by the errors of the world around him, the man who lives his Christian life to the full.
Source: Ecclesiam Suam (Vatican.va)