Someone used the phrase "No cross, no crown" on a mailing list, and explained it as meaning "Don't discuss religion or politics". I was fairly sympathetic with the intent, but unfamiliar with this use of the phrase: I had always understood it to mean "If you don't take pains you won't achieve anything", and to be a specifically Christian metaphor: "No earthly cross of metaphorical crucifixion, no heavenly crown of sainthood." I decided to look into the question.
I quickly checked the first 500 Google references to the phrase, and all of them except three clearly referred to the sense I already knew, drawn from all over Christianity, mostly Catholic and Quaker, but Episcopal, AMEZ, Orthodox, and even Rosicrucian. The Christian Scientist symbol of a cross surmounted by a crown probably alludes to the saying as well. The saying is of course also found in purely secular contexts, with the same sense.
Two of the three exceptions are basically accidental: a song "Ojo por Ojo", which says "And in that place there is no cross / no crown, no sacred ground / all is done and left unsaid"; and a page denying that the Mormon Temple is a Christian edifice, enumerating the Christian symbols that it does not have (at least on the outside): "There is no cross, no crown, no alpha or omega, no icthys, no lion, no lamb, nor any other recognizable historical Christian symbol."
The final exception appears in a speech on Voltaire by Robert Ingersoll, the 19th-century agnostic, who is clearly using the expression in the mode of parody; he associates it with King James I's maxim "No bishop, no King", by which the King meant that if Presbyterianism came to dominate England as well as Scotland, he would swiftly find himself either out of a job or a tolerated figurehead.
The Quaker references clearly allude to a book of that name by William Penn, in which he says, "No pain, no palm; no thorns, no throne; no gall, no glory; no cross, no crown." The modern phrases "No pain, no gain" and "No guts, no glory" are clearly reminiscences of this. I also found "No pruning, no grapes; no grinding mill, no flour; no battle, no victory; no Cross, no Crown!" and "No laming, no naming, no struggle, no Promised Land; no cross, no crown" in the works of others.