I'll start off with a definition of the word moral.
-AdjectiveNow that we know what we're discussing, how do we decide what is moral and what isn't? Religious groups often claim moral superiority, saying that absolute morality comes directly from their said deity. This is the first issue regarding morality that I will be addressing.
1. of, pertaining to, or concerned with the principles or rules of right conduct or the distinction between right and wrong; ethical: moral attitudes.
Does absolute morality come from God?
In order for some absolute moral 'code' to come from some god, we must have some instruction from the said deity. Christians claim the bible, Muslims the Quran etc.. Leaving the issue of inspiration completely aside for the sake of argument we have some serious issues with using an outside source as a moral code. The first problem I see, is that no matter how comprehensive a holy book is on moral issues, it is never going to cover every moral dilemma. For example, the Bible says nothing about climate change; stem cell research; genetic engineering; pollution and many many other modern issues. The same applies to the Quran, nothing vaguely related to any of the previously mentioned issues arises in this holy book either. So if we can not derive morality on these issues from holy books, where do we get it from?
If I was to ask most religious people where they get their morality from, they would promptly reply 'God' or 'The Bible'. If I was to pose the question 'If god told you to kill your child would you do it?' and you replied 'no, god wouldn't ask for that', then you are not deriving your morality from god, but from some other source which you are not aware of. On the other hand, if you were to respond saying 'yes', then I believe you are amoral, and would kindly ask you to stay away from me.
So what is this elusive outside source of morality? It is quite simple. Most of our moral standards come from our culture, our interactions with others, from our upbringing, from our understanding of reciprocation. A lot of our morality derives from what is known today as the 'golden rule', "do to others as you would have them do to you". And no, Jesus didn't invent this concept. The golden rule arose (most likely independently) in most cultures across the globe, most of which predate Christianity, and either predate or were contemporary to Judaism.
So as to the claim of some religious people that you can't be moral without god, you are wrong. In fact the mere idea that you claim to be morally superior because you have a deity dictating to you what is right and wrong shows your complete lack of personal morals. If you were truly a moral person you wouldn't need an imaginary friend telling you that killing is wrong for you to realise this.