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

[Pnerd]

However, it doesn’t come close to addressing the OP’s question, which is ‘Why, on theism, do humans have a moral duty to be good?’. (Bold mine)

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.