It's simple. It means that once mankind found out the differrence between Good and Evil, he immediately became subject to Satan's(Shatan) influence and fell victim to Evil because Satan made it more attractive than following Good. Mankind is naturally weak and needed a Lord to follow, God knew this. But out of that weakness mankind disobeyed God(Lord) and open the door to Satan's rule over his life. the woe and sorrows of life being felt today(wars, abortions, murders, suicides, etc...) by mankind is a direct result of his disobedience to God and a direct result of following Satan's way, which is the way of the world. Satan says if life is too hard, kill yourself. God says, if life gives you lemons, make lemonade. This is why I've always said that mankind was born into Hell(sin) but God left us a life raft to get back to where he is in heaven. it's up to us(individually) to seek that escape route life raft.