"What does the Bible say about altar calls? Are altar calls biblical?" Answer: The practice of altar calls—calling people forward after an evangelistic sermon to make a public confession of faith in Christ—has gained prominence in the 20th century primarily through "crusades" such as those of Billy Graham. Also known as the "invitation system," altar calls are regularly practiced as part of some church services, especially in many Baptist denominations and other evangelical churches where altar calls are an integral part of the services.