It seems to me that what constitutes sin is anything that is contrary to the biblical gods laws or in some personal way offends him. But apparently nothing pisses God off more than the sin of idolatry? What is idolatry you may ask and how do I know that this makes the imaginary guy in the sky very angry? Because it is right there in black and white in the "holy bible" God's written record to man about what his likes and dislikes are and his very own false version of history.
Idolatry is basically the worshiping of other gods through the use of graven images and rituals. Some say idolatry extends to loving something more than god, like the love of money for instance. But in its most basic sense I speak of it as defined in the first sentence of this paragraph. In the book of Leviticus (law) chapter 20 the Hebrews are given the famous ten commandments and the first thing that God lets the people know is that : 3 'You shall have no other gods to rival me.4 'You shall not make yourself a carved image or any likeness of anything in heaven above or on earth beneath or in the waters under the earth.5 'You shall not bow down to them or serve them. For I, Yahweh your God, am a jealous God and I punish a parent's fault in the children, the grandchildren, and the great-grandchildren among those who hate me; Leviticus 20: 3-5 (NJB).
The commandment pretty much defines idolatry for us and it specifically prohibits the making of graven images of gods and other things. So my question is why is it that the so called "one true Christian church" (Catholicism) as they like to call themselves have so many graven images and even encourage the veneration of them? I debated an Catholic apologist on this issue once for weeks. He basically stated that they don't worship saints etc. they venerate them and pray for them to intercede on their behalf before the Lord.
Before we continue let's define the words worship and venerate in the simplest way possible. According to my Sage dictionary the word worship means: 'To love unquestioningly and uncritically or to excess;venerate as an idol.' The next word we need to look at is venerate and that is defined as follows by the same source: 'Regard with feelings of respect and reverence; consider hallowed or exalted or be in awe of.' As you can see there is not much difference between the two meanings. The Catholic church "venerates" the people that they have canonized as saints. But this so called veneration is no different from the biblical definition of idolatry because they have graven representations of these saints who they perform certain rituals for in order to approach them and gain their favor.
Now let me give you my understanding of what sin is. It is whatever the biblical God says it is and nothing more. There are many instances in the bible where God's commandments were allowed to be broken as long as they were being led by God himself. The most common one was the command to not kill, but if you took the time to read the old testament you will quickly see that the Hebrews did exactly that. With the guidance of their God and human leaders they led a campaign of conquests of the so called promised land that included massacring whole populations.
On one occasion the people were complaining to Moses about how hard it was for them walking in the desert suffering hunger and thirst when they had it all in Egypt. When God heard this he was angered and loosed a plague of serpents in the camp that began biting and killing some of God's people. When the people begged Moses to pray so that this plague could be taken away guess what happened next? After praying he received these instructions from the good Lord: 8 and Yahweh replied, 'Make a fiery serpent and raise it as a standard. Anyone who is bitten and looks at it will survive.'9 Moses then made a serpent out of bronze and raised it as a standard, and anyone who was bitten by a serpent and looked at the bronze serpent survived. Numbers 21: 8,8 (NJB).
God basically told them to commit idolatry by making an image of a serpent out of brass so that those that looked upon it could be saved. Why couldn't he have just had them all perform some ritual or sin sacrifice instead? Because no sin is a sin unless God says so. After the plague had passed what do you think happened to that brass serpent? According to the scriptures King Hezekiah had it destroyed because apparently the Hebrews were worshiping it. 4 He abolished the high places, broke the pillars, cut down the sacred poles and smashed the bronze serpent which Moses had made; for up to that time the Israelites had offered sacrifices to it; it was called Nehushtan. 2 Kings 21: 4 (NJB).
In closing I've always said that the bibles many contradictions don't present God in the best light. He is seen as flawed, self-contradictory and a far cry from omniscient (all knowing). I believe that the reason that the biblical god appears so human is because he is a human creation. Just like all the other gods before and after him he was just another product of the very creative imagination of a people. He is a myth and a superstition that even hangs around today because people refuse to acknowledge these facts and recognize what he is and where he came from.