I am slowly working my way through Hinduism by R. C. Zaehner and trying to understand dharma. This word is often translated as duty, but it has much broader meanings than that. Your dharma is the set of obligations you have because of your gender and your position in the caste system. One person cannot gain merit by performing another person’s dharma. The Brahman’s dharma is to study the scriptures and perform sacrifices. A Sudra’s dharma is not to hear the scriptures, lest he defile them.
I can compare this set of obligations to Abraham’s aborted sacrifice of Isaac, “the binding.” Reading this portion of the Torah is traditional on the morning of Rosh Hashannah and the story always gives me a chill. So what was Abraham’s obligation? God called him to worship and to obey, then gave him the most difficult task: to kill his son. Abraham interprets the issue as one of obedience — God directs and he obeys. But does that make it right? Is an act good because God wills it, or can it only be good if it meets some other test?
One response in Hinduism is that while we each have our own individual dharma, our own duties to perform, there is also an eternal dharma which the individual dharmas serve. While for God to instruct Abraham to slay Isaac seems wrong to us (and may have seemed wrong to Abraham also), it serves God’s larger purpose to establish that child sacrifice is not required.