Following a medical illustration, if a doctor diagnoses a disease incorrectly, the cure he/she will prescribe will only correspond to the severity of that disease or possibly just the symptoms. The majority of theological positions held in churches or by individual Christians begin with Christ, and start their apologetic at the cross. These positions vary in degree significantly as to what exactly Christ accomplished.
What is usually overlooked or taken for granted, given its unpopular nature, is the doctrine of sin. Offering the victim of a car accident the options of counseling, a band aid, a tourniquet or resurrection (if dead) are vastly different options (the last option being against his ability to choose). It is the status of the victim that warrants which of the options is appropriate. Believing what Christ accomplished will greatly influence the teaching and preaching of any church and therefore the witness carried out by the congregation.