On theism, why do humans have moral duties even if there are objective moral values?

[Pnerd]

Thank you for pointing that out. Many of the answers here haven't answered my question, which was "Why, on theism, do humans have a moral duty to do good or be good other than for a selfish interest in going to heaven or avoiding hell?". Most replies here answered some other question.

I think I answered your question very accurately. Worship god = good, don't worship god = bad, don't worship god but then take it back = good.

When it comes to gods,......... humans make funny rules.

(I noticed that you have not rep'ed me, look out, you might get smited)

I'm not asking about worshipping; I'm asking why theists believe they have a moral duty towards other humans (I agree that was not made clear in my question). And secondly, the last part of my question was "other than for a selfish interest in going to heaven or avoiding hell". Your answer seems to be about god's reward and punishment as a motivation for theists to do good. By the way, why is worshipping god = good according to a theist (other than divine reward/punishment)?