Righteous and Nefarious

How do we know what to believe? How do we know what's right and what's wrong? Society tells us to follow our hearts, but that's a biased opinion, isn't it? In fact, everything we are ever taught is biased! Kids that go to school learn what the government believes. When they go home and watch tv they learn what's generally accepted, or what society believes. Kids who are homeschooled learn what their parents teach them. Kids who go to church a lot learn what their pastor believes. Our opinions are shaped by other peoples opinions. So how do we know what's right? Well let's follow our hearts like society tells us. That usually does not end us up in a good place. If our "heart" tells us that drugs, smoking, or drinking is cool, we may end up addicts. If our "heart" tells us to do exactly the opposite of what our parents say, we will end in trouble a lot. But a conscience plays a role in there somewhere, right?
All people have a general agreement on what is right. People all through history have agreed on general things like, "it's not right to murder," "it's not right to rape," "it's good to be caring," "it's good to be skilled," etc. But where do we truly get that sense of good and bad? Righteous and nefarious? That's when we start to look outside ourselves. In the past people would make up gods. Many had the qualties of physical things - the sun, the moon, water, fire, etc. But there was a religion called Zoroastrianism that a man named Zoroaster created. He wanted to eliminate the polytheistic system of religion, and turned to a dualistic sytem of religion. He claimed there were two gods: The good god - Ahura-Mazda (Wise Lord) and the bad god - Ahriman (Destructive Spirit). The good god created supposedly created the world and does only what is right. The bad god continually opposed him and battled Ahura-Mazda for control of the universe. Zoroaster believed the earth would last 12,000 years and a messiah, Sashoyant, would come at the end and help Ahura-Mazda defeat Ahriman. Now if this religion was true, where did the good god get his idea of right? And why does the bad god enjoy wrong? How do we know that the good god isn't actually bad and everything we know to be right isn't actually a distorted sense of bad?
Our consciences all have a general sense of right and wrong, so we are still at a loss of where that idea of good and bad, righteous and nefarious came from. Suppose there was one Creator. He had more knowledge than humans, and created right and wrong to begin with. It makes sense, then, that everyone would have a general agreement on right and wrong. And isn't that what we see? Even people who murder or steal usually have a reason behind what makes them think their actions are good. A person might kill someone because that person wronged them. They might steal because they have no money and their stomach is telling them it needs some love. If needed, people will do "wrong." But how do theys know they are wrong?
What I believe is that God has always been there. (hard to imagine, but true) He has always known good and bad. Righteous and nefarious. He created the universe, and wrote His law on our hearts. Look for yourself, but as for me, this is the conclusion I always come up with in the end.