"Sign of contradiction" is a term refers to certain persons who, upon manifesting holiness, are subject to extreme opposition. The term is derived from the biblical phrase "sign that is spoken against" ("a sign which is contradicted") found in Luke 2:34 and in Acts 28:22, which refer to Jesus Christ and the early Christians respectively.
In his book, Sign of Contradiction, John Paul II said that "sign of contradiction" might be "a distinctive definition of Christ and of his Church."