Matthew Mullins writes for Prosblogion, summarizing an argument that purports to show that the Divine Command Theory of morality (DCT) is inconsistent with the idea that we have a moral obligation to worship God:
1. If DCT is true for any act X, we have a moral obligation to do X (or refrain from doing X) if and only if God commands us to do X (or refrain from doing X). (The Obligation Principle)
2. If DCT is true for any act X, if God commands us to do X (or refrain form doing X), then we have a moral obligation to comply with Her command to do X (or refrain form doing X). (The Compliance Principle)
3. If it is impossible for a person to perform some act X, then it cannot be the case that she morally ought to do X, and, more particularly, it cannot be the case that she is under any moral obligation to do X. (Ought-Can Principle)
4. In order to fulfill an obligation to comply with a command, one must comply because one has been so commanded.
5. Genuine worship is by nature voluntary.
6. If genuine worship is voluntary, then one cannot worship because one is commanded to do so. [1,4,5]
7. It cannot be the case that God commands us to worship. (3,2,6)
8. If DCT is true we have no moral obligation to worship God. (1,7)
Mullins disagrees with the argument, focusing primarily on #6: must worship be voluntary? Campbell Brown and Yujin Nagasawa, the two who constructed the above argument, say genuine worship must indeed be voluntary. Millins argues:
[I]t is not clear to me why worshipping God out of a moral obligation would be insignificant or empty. The problem seems to me that Brown and Nagasawa mistake what it means for the theist to worship. Worship is not simply an emotional response to God or an simple act of genuflecting. For theist of the Christian persuasion worship is a bit more complicated than simple praise.
Mullins then goes on to quote Baker's Evangelical Dictionary of Biblical Theology which describes “true worship” as an “essentially internal” matter that is “rooted in the knowledge of and obedience to the revealed Word of God.” It doesn’t seem entirely unreasonable then to agree that “worship” is more than “simple praise,” but it’s not at all clear that the concept of “worship” in the above argument is limited to “simple praise.”
The authors define worship as being motivated by a sense that God is praise-worthy, but that does not in any way mean that worship is, thus, just praise. For example, if I “worship” a person and that worship is motivated by a sense that that person is trust-worthy, does that mean that my worship consists of nothing but trust? It’s possible that it might be, but I see no good reason to draw that conclusion. I might do a lot more than trust this person, but whatever I do it is because they are worth trusting.
Similarly, whatever form my “worship” of God might take, the argument above presupposes that my worship is because I find God worthy of praise and that, in turn, can only be a state of mind that is completely voluntary. I cannot be commanded to find God praise-worthy; if that is true, then I cannot be commanded to worship God.
Of course, one can frame a similar objection differently. For example, one might argue that “true worship” need not be motivated by finding God praise-worthy but, rather, by finding God fearsome and wrathful. Could such states of mind be commanded? Perhaps, I’m not sure — but I’m also not sure about the value of any “worship” that it so motivated. There seem to be two types of possible motivation here: emotional (love, fear) and assessments about the character/nature of that being worshipped (praise-worthy, trust-worthy). Neither type seems to be of the sort that could be commanded.
Does any of this really matter? Absolutely. If we do not have a moral obligation to worship God, then those who do worship God are not thereby acting in a morally good way and those who fail to worship God are not thereby acting in an immoral way. There is nothing morally praise-worthy about worshipping God and nothing to morally condemn about not worshipping God. This contradicts a position taken by many Christian theists.