 Martin Luther believed and taught that the church had strayed and fallen away from the true teachings of the scripture.He challenged the authority of the Pope of the Roman Catholic Church by teaching that the Bible is the only source of divinely revealed knowledge, and opposed sacerdotalism by considering all baptized Christians to be a holy priesthood.Although Lutherans and Calvinists hold that the Ecumenical Councils of the early and medieval church are true expressions of the Christian faith, many assert that the councils are at times inconsistent with one another, and err on particular points.