This very short post is inspired by that small band of theists, notably Christian theists, who seem to have great difficulty understanding why most non-theists and atheists are intrinsically just as moral as most theists.
Imagine yourself in a small room. You have never heard of any god and you are asked to make a simple choice. There are two doors A and B, each of which lead to a secular world. Door A leads to secular world A which is governed by two simple rules. Rule 1 of this secular world A is dog eat dog. Rule 2 of this secular world A is survival of the fittest.
Door B leads to secular world B which is governed by three simple rules. Rule 1 of this secular world B is love your neighbour as yourself. Rule 2 of this secular world B is treat others as you want to be treated. Rule 3 of this secular world B is failure to observe either of the first two rules results in instant transfer to world A.
You have free will. You have all the information you need to make a choice. The choice is yours. Which world would you choose to live in?