Question: Is the conscience a sufficient guide for man?
No. Conscience, using the word in the sense of the moral intuition that every person possesses that right is right and wrong is wrong, and that each of us ought to commit to following wherever it leads us, is sufficient to lead us to an absolute surrender to do what is right, whatever it may be. However, then there comes the question of what is right. Conscience, in the sense of moral judgment as to what is right or wrong, is certainly not a sufficient guide for man. Many people conscientiously do things that are utterly wrong because their moral judgment has been improperly educated. Conscience needs to be enlightened by divine revelation and by personal illumination of the Holy Spirit as to what is right.
If we surrender ourselves to doing what is right, wherever it leads us, and if we make an honest search for what is right and true, we will be led to see that Jesus Christ is the Son of God and a Teacher sent from God (Matthew 16:16; John 3:2; 7:16-17). Then we will bring our moral judgment to Him for education. Having accepted Jesus Christ as the Son of God and a Teacher sent from God, we will logically be led by the study of His Word to accept the entire Bible as the Word of God, and we will consequently take it as our guide in conduct. Furthermore, we will be led to see that it is our privilege to be taught by the Holy Spirit and to be guided into right conduct by Him.
~R. A. Torry~