What are the similarities in Bible, Quran and Bhagvad gita?

Once I had to write an essay on Mahatma Gandhi. I read some articles on him and a short book covering his major life events. I came to know an interesting fact about him. He read Bible, Quran and Bhagvad Gita to connect effectively with Christians, Muslims and Hindus. I liked his idea and I decided that one day I would also read these religious books.
Finally, I have read them. I have observed that there are 21 common messages in these books and they are as follows-

1.      There is only one God of this Universe

2.      He is formless and believe in Him

3.      Remember God through prayers

4.      Preach about God and His creations to other people

5.      No religion matters to God, only your truthfulness matters to Him

6.      God gives us life and He only kills us

7.      We are responsible for our actions

8.      God gives us rewards and punishments for our actions

9.      Earth is only a resting place for us

10.  Every living thing has a Soul

11.  Angels, Hell and Heaven exist

12.  Good people go to Heaven and Bad people go to Hell

13.  Idol worship is the lowest form of worship

14.  Don’t find God in idols

15.  Give respect to the resources that He has given to you

16.  Give charity to the poor and needy people

17.  Do not lie

18.  Do not steal

19.  Do not commit adultery

20.  Do not hurt people physically or emotionally

21.  Speak gently
These messages may sound general or common to few but it's a FACT that all these books talk again and again about these 21 messages only.