What IS good, and how do we determine it?

[Aoi Magi]

What the heck do you mean by "moral truth"? Define the term please...

1) If murder or any such action is morally wrong in one situation but not wrong in another, and if the same morality isn't universally applicable then morality is NOT a universal truth, but a subjective truth.
2) If it is subjective, then suggesting it is universally defined by a supreme being is false.
3) Thus simply presuming a supreme being, and jumping from that to christianity or any particular god is a huge leap in logic.

It means that it IS immoral regardless of what some people believe. So, going around butchring infidel men, women, and children for the sole reason that they are not radical Islamists, is immoral, period. This is a moral truth.

I keep using Isis as an example because it's the big thing going on right now. But it's just an example and is not limited to them.

I agree with your point #3.

Has this situation been precisely written down in the religious moral-handbook or on the contrary does it actually advise to do the same thing as what ISIS is doing? Even in NT the threat is there albeit in a softer tone

Matthew
10:14 And whosoever shall not receive you, nor hear your words, when ye depart out of that house or city, shake off the dust of your feet.
10:15 Verily I say unto you, It shall be more tolerable for the land of Sodom and Gomorrha in the day of judgment, than for that city.

But leaving that aside, I am glad you agreed to my #3, but I'd also like to hear your thoughts on #1 and #2. If morality doesn't exist in nature why do you believe it to be universal?

Even if it is objective why does it need to come from a supreme being but not from within our societal norms or as you say, our "instincts", as there is clear evidence of morality changing throughout time as our society evolved?

If you only explain your morality only from your particular religious text, then what about situations that are not covered in that text? Like say killing fish and animals for food....