Baptists and other believers-church traditions affirm credobaptism, that baptism is properly administered only to those old enough to make a personal profession of faith, and not to infants. On this view baptism is the response of a conscious believer to the gospel and a sign of a faith already professed, so it belongs to those who can repent and believe for themselves; many of these traditions practice it by full immersion, seeing it as a symbol of dying and rising with Christ. The New Testament pattern of preaching followed by the baptism of believers is cited as the warrant, alongside the absence, proponents argue, of any clear New Testament instance of an infant being baptized.
The conviction has an identifiable origin point in the Swiss Reformation: in Zurich in the mid-1520s, a group later called the Swiss Brethren, including Conrad Grebel, broke with the city's official reformer Huldrych Zwingli specifically over infant baptism, and performed what the authorities considered the first adult rebaptisms of the movement, taking the name Anabaptist, re-baptizer, from opponents who viewed the practice as a repeat and therefore invalid or blasphemous act rather than a first true baptism at all.