I'm very curious: from where did you hear that atheist think that morality comes from survival instinct? I've never heard an atheist saying that. I think they would be wrong to say so, because survival instinct is more of a process that tend to overpass moral actions (putting in daylight our inner animal's behavior, which are to survive no matter what the cost is).
About morality, I'm more of the Kant philosophy: morality comes from reason and logical thinking.
Now about theist. You claim (well, some of them) that morality comes from scripture. Let's take Islam (this forum belonging to members of this religion). When you say, as Kurisu mention, that
Allah is the source of all morality
,
am I right to assume that you get your morals (as you say) from the Qu'ran.
So Allah--->Qu'ran---->You
So, if your morality coming from your scripture (so from Allah), you should do
EVERYTHING of what the Qu'ran say, even the nasty parts. The same thing should apply to Christian and their Bible, Jews and their Torah, Hindus and their Vedas, and so on...
BUT! When the Qu'ran says to kill every muslim who leave islam for an another religion, I don't think you do it (I'm relaying on hope and faith on that one). So if you don't, is it too much of an assumption to claim that you don't because it would be immoral to do that? Then, you have the ability to pick and choose in the Qu'ran what's moral and what is not. But how do you do that, if your morals come from the Qu'ran? You see, if you can do that, you already have this ability inside you. The same apply to Chritstians who claim that their moral comes from the bible.
So if we already have that capacity inside ourself, why only limiting ourself to the Qu'ran, the Bible or the Torah. As far as I know we could use Harry Pother or the dictionnary. Some people like me thinks that morality comes from logical thinking (like me) , others think that it comes from emotion, social rules or evolution (like Richard Dawkins). It is surely a mix of all of them.
To the people who claim that their morality comes from their scripture, whitout exception (about their morality, not their scripture. Bhuddist are fine:D ), you are saying that the only things that keep you from killing your neighbor, raping his daughter and stealing all his stuff is your fear of afterlife or from Allah/God/Yaweh, I will ask you this:
Please, stay the **** away from me, my family, my friends and from any other creature capable of suffering that has the bad luck to be near you. And avoid at all cost any conversation with a non-believer, may he be an atheist, humanist, secular, agnostic, or else. Please, for humanity's sake, continue to believe and good luck with your faith