The reason we know right from wrong is not simply because man recorded God’s words in The Bible and not because society tells us or conditions us into our moral code of conduct. We know right from wrong because God is written in our hearts, along with His rules and laws governing our behavior. This means that we inherently understand what is good and bad for us, and those things are rooted in what most would call their conscience. I know this not because I read it somewhere or because somebody else told me so. I know this because only AFTER I already realized that God is my conscience and knew that He wrote these things in our hearts (my verbatim thoughts), I found the following scriptures: “But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts, and will be their God, and they shall be My people.” – Jeremiah 31:33. “For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another; – Romans 2:14-15.
As we draw nearer to God, he instills in us this supernatural ability to discern His voice distinguishing right from wrong and good from evil. To the point where we often instinctively know things that there is no other explanation for knowing (for example, how I knew that God’s laws were written in my heart and then later I discovered that He even tells us that He wrote it in our hearts in Jeremiah 31:33). The further we separate ourselves from God, the less we are able to distinguish these things, to the point where we suffer from what is called spiritual warfare. We still hear God but we choose to ignore Him. We blame society for the way we feel when, had we listened to God, we would know ahead of time what kind of consequences could be expected from our behavior. Without this spiritual/supernatural discernment, we struggle with the spiritual warfare going on inside our hearts because we know we are not doing right by God. Spiritual warfare often leads to depression and even suicidal tendencies. And, if we’re not careful, if we tell God enough times that we don’t want Him, He may very well leave us alone as He has been known to do in the past. “And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient; – Romans 1:28.
Many times people question laws from the Old Testament using them as an example comparison to current issues that are sins by God’s standards. But many of these Old Testament laws were instituted for a specific time in history, for a specific group of people, and for specific reasons. In fact, a lot of the Old Testament laws weren’t even God-given laws; they were societal laws so they wouldn’t even apply when we’re talking about God’s laws. This is the reason that we don’t naturally think about those things. We don’t naturally question in our hearts whether it is morally right or wrong to wear clothing of mixed fabric because that law was not part of the God-given commandments that He wrote on our hearts. If it isn’t written in our hearts, it’s because it doesn’t apply. However, we cannot confuse “not written in our hearts” with the deliberate refusal to hear God and ignoring of our conscience.
That is not to say that nothing in the Old Testament applies today, because it is certainly just as relevant a part of the Bible as the New Testament – and it was always wrong to lie, steal, murder, etc. A general rule of thumb is that if you’re not at peace with a decision or action, or if you’re questioning in your own conscience the morality of something you’re doing, there’s a reason – it’s because God has already spoken on the subject and wrote how He feels in our hearts.
God even gives us instruction for when man’s law conflicts with God’s law, so we should never be confused if we are commanded by a law of the land that goes against our conscience: “Then Peter and the other apostles answered and said, ‘We ought to obey God rather than men.’” – Acts 5:29.