Adam and Eve's sin started it all, correct? What about Lucifer? Lucifer's fall came first, but why didn't that result in the common habit of sin already? I know he was a fallen angel, but was he the real cause of sin, or was it Adam and Eve's disobedience?
Good question. Well Lucifer was an angel of God. Not of human beings on earth. So Adam and eve broke first of God's rules and laws on earth as humans as of man and woman. Not much is written or know about what happened before God created man with his angels. Just that Lucifer was one of God's angels and turn away from God. . But all is of God's will. God figure man needed to have free will to have choices. So by allowing or creating Lucifer to do what he did that allow us to have free will of choices.
Sin, singular, is the absence of spirit. Adam had a spirit but it died and so he was unable to bequeath a spirit to his offspring. That is why everybody is born in sin, not because Mommy and Daddy did the big nasty. That is why a savior had to die in our place and make it possible to create a new spirit for us.
Sins, plural, are mistakes, such as throwing a dart and missing the bullseye. Christians are baptised into Christ's death, and dead bodies don't sin, so sins are not an issue for Christians. There is no more forgiveness. Either you believe in Jesus and are saved or you don't believe and are lost.
Satan is a spirit, so sin does not apply.
I thought I had posted this answer to you before. Did you not like it?
Sin started in the mind of man, sin started when man forgot about God. It is said that God made Adam and Eve out of himself and put in them the Divine Spirit because there is none other than God. Unfortunately, Adam and Eve forgot God was within them. They got lost in the world of material pleasures and so they forgot that they were a manifestation of the Divine. So where did sin start? Not with Adam and Eve, but in the mind of man. In the fact that we forgot God. The moment we become conscious of God's Divine presence within, there will be no sin and we will be liberated and achieve salvation.