The only way a person may be saved is to adhere to what Christ taught through His Church. The notion of "once you accept Christ as your Savior you are saved e.g. eternal security" is false because according to the Bible, it is possible for a Christian to fall away from the grace of God and go to Hell.
The issue on the Bible's teaching on how a person is saved is the most important issue for all of us. If works and things you do, and sins you must avoid are part of whether or not you are saved, it only follows that God would have founded a Church to authoritatively set forth and maintain His truth to instruct people more specifically on Christ's teaching about what they must do for salvation.