In one of his pornolinguistic papers, James D. McCawley, writing as Quang Phuc Dong of the South Hanoi Institute of Technology (beating Accepted to the joke by about 40 years) explores subjectless sentences like "fuck you" and "damn you." He argues convincingly that they are not imperatives, but is unable to advance a meaningful alternative analysis.
One of the alternatives that he considers and discards posits that such sentences have God as the subject in their underlying representations, followed by a deletion transformation creating the appearance of subjectlessness in their surface representations. Like so:
UR: God fuck you.
DT: God --> Ø
SR: Fuck you.
Besides accounting for the absence of a subject, this analysis has the advantage of being acceptable to both atheists and theists. Atheists can call it "God-deletion," while theists can invoke the hidden hand of God.
Ultimately, this analysis doesn't work. Besides not being very explanatory, there is the fact that you cannot say *"Fuck himself" to mean "fuck God.," but you can say "Fuck God" to mean "Fuck God." This should not be possible if God is the hidden subject.
So subjectless sentences are not good evidence for God. But there is better evidence from Hebrew negative imperatives.
As I think I pointed out in my masters thesis (I haven't organized my books since I moved last month, and finding the thesis would be a hassle), the normal way to express negation in Hebrew suppletive imperatives is with the use of the negative al:
(1) al tircax oto!
neg murder.2.masc.sg.fut him.DO
"Don't murder him!"
However, if God is issuing a commandment, the proper form of the negative is lo:
(2) a. lo tircax!
b. ?al tirtzach!
"Thou shalt not kill!"
The sentences with al is shown with a question mark to indicate that the utterance, while not unacceptable, is ungodly. That is, if God uttered (2b), it would be interpreted as carrying less than the full authority and timelessness of one of God's commandments.
The pattern in (1)-(2) is decent prima facie evidence of the existence of God, at least as a morphological phenomenon. I propose to formalize this by subscripting either [+God] or [-God] to morphemes, depending on whether they are or are not godly. Thus al would be represented
Neg[+imp, -God]
Neg[+imp, +God]
Can God use al? Yes. If God was speaking to a person in a more private capacity, rather than issuing universal commandments, Gods would use al. In fact, he did so all the time in the Bible. So for example, when God played a practical joke on Abraham, and had him bind Isaac to an altar and get ready to sacrifice him, he used al to tell Abraham not to harm Isaac after all. The key to godly language is that it expresses a universal, principled prohibition, not just a particular "don't do this."
I know of no evidence of the existence of God in nonimperative morphology. There are many mysteries in the morphology of imperatives, both in Hebrew and more universally. Whether the presence of God in imperative morphology advances linguistic research remains to be seen. But it sure is fun to think about.