Morality is the word we use to describe how we wrestle with the way we should or should not act in relation to others.
We have to decide on our objective - for example promoting the well-being of conscious creatures. Then we weigh up whether a proposed action advances that goal. This is all we actually mean by 'should' or 'should not' or 'right and wrong' or even 'good and evil'.
It is a moral fact that doing gratuitous injury to others is always 'bad'.
Christians complicate things by inserting an additional layer - the wishes or commands of a divine law-giver. But the law-giver has nothing to say about so many of the dilemmas that we face. In the case of the god of the bible we are faced with a law-giver who approves of things we all find repugnant. The truth is we have to filter god's moral commands by using the same rubrics that atheists use. In other words god is useless as a moral guide.