What does the Bible say about this? Can it be shown that God demands more than just belief? A quick example should answer that question: We read in John 12:42 of many of "the chief rulers ... (who) believed on Him; but because of the Pharisees they did not confess Him, lest they should be put out of the synagogue." Were these "secret believers" acceptable to God? Did He put His stamp of approval upon them? The next verse, John 12:43 tells us, "For they loved the praise of men more than the praise of God." The thing that was missing in this case, as in so many, was obedience to God's will as a result of faith. Abraham shows us that: Abraham was a giant of faith in the Old Testament. It is said of him, Genesis 15:6, that Abraham "believed in the Lord, and he counted it to him for righteousness." But, Hebrews 11:8 tells us a little more about that example of faith; "By faith Abraham, when he was called to go out into a place which he should after receive for an inheritance, obeyed; and he went out." By faith he obeyed. The Apostle Peter reminded some Christians, "Seeing ye have purified your souls in obeying the truth."(I Peter 1:22) The question that needs to be answered is this: Were their souls purified when they believed, or when they obeyed? Peter says, "when they obeyed". James tells us in James 2:24 that "By works a man is justified, and not by faith only." Works of obedience, or as Matthew 7:21 says, "Doing the will of the Father."
God expects us to do more than just believe; He expects us to follow His pattern of life that He has revealed through the Bible. And it is only right that He do so; for His own Son did more for us than "just believe": Philippians 2:8 relates that Jesus, when He came to earth, "Humbled Himself, and became obedient unto death, even death on the cross." Peter says that Christ, "left us an example, that we should follow His steps."(1 Peter 2:21) And so we shouldn't be surprised that Hebrews 5:8-9 says that Jesus "learned obedience by the things which He suffered; and being made perfect, He became the Author of eternal salvation unto all them that obey Him." Not just believe in Him, but also obey Him. Jesus said in John 8:32, "Ye shall know the truth, and the truth shall make you free." But that can only be true if we do the truth that we learn. It was said of the Old Testament character Ezra, in Ezra 7:10, that he "had prepared his heart to seek the law of the Lord, and to do it, and to teach in Israel statutes and ordinances." Ezra decided to seek the law, so that he could do it, and teach it to others. I know that Ezra, from that frame of mind, surely found the law of God he sought. For John 7:17 assures us, "If any man will do His will, he shall know of the doctrine, whether it be of God, or whether I speak of myself." If your intent is to do the truth, God promises that you will find the truth.
Is obedience necessary? Hear a last warning from II Thessalonians 1:8-9; Jesus will come again, "In flaming fire taking vengeance on them that know not God, and (them) that obey not the gospel of our Lord Jesus Christ, who shall be punished with everlasting destruction from the presence of the Lord, and from the glory of His power."