The law knows nothing of mercy; the gospel knows nothing else. By the Law I learn that I am guilty, but by the gospel I learn that I am guilty, but by the gospel I learn that I am justified freely by His grace through the redemption that is in Christ Jesus. By the law I learn that I have ruined myself by sin and stand exposed to Divine vengeance, but by the gospel I learn that the Lord Jesus was made sin for me that I might be made the righteousness of God in Him. By the law my hopes are destroyed, and by the gospel my expectations are raised. By the law I am stripped, exposed, condemned, and slain; but by the gospel I am quickened, justified, accepted, and clothed.
To trust Christ Jesus alone is to depend upon Him, to definitely, deliberately receive Him as Lord and Redeemer. It means to trust Christ so utterly and completely that should He fail, THERE IS NOTHING ELSE! It is not Christ and the church, Christ and baptism, Christ and my faith; it is not Christ and anything else. CHRIST IS ALL OR NOT AT ALL!
Jesus Christ is not a pasteboard king with royal titles and no authority. He sits upon His holy hill, invested with all power to capture the hearts of His subjects and to execute His threatened vengeance on His adversaries; and where He brings men under the rule of His sceptre, He bestows the blessings of His kingdom.
Church membership does not make a person a Christian anymore than owning a piano makes one a musician!