The entire Christian system centers around the death of Jesus on the cross. He “died for the ungodly” (Rom. 5:6, 8). He “laid down his life for us” (1 John 3:16). In spite of numerous like statements of Scripture, certain things, if true, would mean that Christ died in vain.
If one can be saved by Law of Moses: Paul argued: “If righteousness is through the law, then Christ died for nought” (Gal. 2: 21b). The Galatians had fallen victim to Jewish Christians who sought to bind at least parts of the law (i.e., circumcision, 5:2–4) upon the church. If Moses’ law could have saved, the Word need never have become flesh (John 1:14), for men had had that law for 1,500 years by the time of Jesus’ birth. The law was only a “tutor” that pointed to the Christ (Gal. 3:24. Its sacrifices were merely typical of the “Lamb of God, that taketh away the sin of the world” (John 1:29). Jesus slew the authority of Moses’ law on Calvary (Col. 2:14). All who justify their religious practices by it (e.g., sabbath keeping, a priesthood, instrumental music in worship, et al.) render the death of Jesus worthless.
If Jesus approves of religious division: Though such diversity is applauded by the masses, the Bible condemns it. Jesus built only one church (Mat. 16:18), and He prayed that His followers be one, as He and the Father are one (which includes doctrinal unity) (John 17:20–23). He died to establish this one body (Eph. 2:16; 5:25). If Jesus is as pleased with the monstrosity of denominationalism as with the one church He established, then He died for nought in that regard.
If the church is non-essential: Jesus “bought” His church with His blood (Acts 20:28). Jesus yes, the church no is a common, albeit grossly mistaken, concept. If one is speaking of man-made counterfeits of Jesus’ church, it is true; He died for none of them. However, to include His church in this concept implies that Christ paid the price for it in vain. His church consists of those who have been saved through His death upon their obedience to Him (Rom. 5:10; cf. Acts 2:37–38, 41, 47).
If I am lost: Jesus’ death will have been wasted, as far as I am concerned, if I am lost. This will not be the case for others, of course. He “gave himself a ransom for all” (1 Tim. 2:6), so all have the opportunity to be saved, but if I am lost, He may as well have spared Himself the misery of the cross. His death will have been wasted on me.
It behooves each of us to obey His plan of salvation (Acts 2: 37–38), whereupon He will add us to His church (v. 47). We thereby accept the salvation He offers. Only by obeying Him and faithfully serving Him may we personally attribute fitting value to His death.