If it wasn't for religion

[Acrobat]

Reason is dependent on objective truths. 

Before you even bother arguing why killing is wrong, you need to hold that you ought not do what's wrong.

If you ought not do what's wrong is not an objective truth, then absent of it, when you provide the reasons for why you find something wrong, it would at best be akin to providing us the reasons why you think Pizza Hut makes the best tasting pizza, or why you like Italian food more than Indian food, etc. Or in other words you moral claims becoming nothing more that decorative frills of personal opinion.

Well, how about we solve the issue I'm pointing out first before we address further contentions. Because I haven't seen any theist to date provide a satisfactory answer to my point.

Suppose your beloved god (whoever it may be) exists. God declares to you (somehow) that killing is wrong. How does this answer the question of what makes killing wrong? Is it really just because God says so? In such case, it would be subjective to what God is about and therefore not really a morality worth having. Even if I'm expected to just go with what God says because he is God, my moral intuition tells me that something is off about believing killing is wrong just because God says so. It has to be more than that. God may be able to assert that killing is wrong, and demand people accept that, but positing his existence does not logically adequately explain why killing is wrong in the first place.

This is a problem that you need to solve first before we can move on to other objections to secular morality. If you can't solve this one, then it seems like theists and atheists are pretty much generally in the same boat when it comes to morality. God does not explain morality, so no need for God to exist for objective morality to be possible. At best, a god can assert or submit that something is morally right or wrong, but that's about it.

No we don’t need to resolve that, because what you and I mean by God, or whatever relationship your conception of God has to do with morality, is irrelevant or unecceary to any point I’ve made.

The only thing you should concern yourself with is the things I told you I believe in, whether or not you understand the relationship between that and Christianity etc, or the Christian God is irrelevant.