You say he began to teach them, but to teach them what? One of your god's 10 commanded is Thou shall not kill/murder. God then demanded that people stone to death other people if they broke his laws. Clearly we have a contradiction. Then he comes back as Jesus at a later date asking everyone to forgive.
Now don't answer, "I don't see contradiction in your statement !" because there is definitely one.
Another contradiction, why did he make a bad fruit in the Garden of Eden? If he was truly God, why would he want to promote bad decision and leave it for them to do, and why not eliminate the problem in the first place?
The law about killing in the 10 commandments is about pre-meditated murder, not about manslaughter or accidental killing. People falling into those categories found refuge in particular cities.
The laws of stoning you are talking about were specific laws for specific situations. The reason for these laws were because God had set Israel apart, and they had promised to worship him, and him alone and obey all his commands to the best of their ability - he tells them that they must be Holy, because he is Holy.
There are other things you need to realised about these commands, they are like the statute laws that we have now, they are the bare bones of the judicial system. In addition to that we have case law ie the accused comes to court and the judge decides how that particular commandment will be implemented. Its the same with Gods laws. The Israelites, and todays Jews have a whole series of by-laws which they work with to keep the commandments.
For instance, when someone committed a crime punishable be death there had to be two witnesses of good character. They had to be examined very thoroughly by the court, not just about the crime but about how righteous they were as people, ie how well they followed the commandments as well. If they were found to have any inkling of a bad character their testimony was thrown out of court, and only the supreme court, the Sanhedrin, could pass a death sentence, so there was no vigilante justice.
A couple of Rabbis that lived just before Jesus said that any court who sentences someone to death once in 70 years were murderous. They remembered God principle attribute - he prefers mercy rather than justice.
God made us like him with the ability to know that difference between right and wrong, to have an opinion, and a free will, thats why he put the tree of knowledge of good and evil in the garden. He wanted us to be able to choose for ourselves. He gives us that choice now - we can choose to believe in him - or not, but it is our choice and he wont twist our arms up our backs.
Also the difference between us and him is that he constantly and consistently chooses to do good, where as we, because we are human, dont.