You can read it here:
In my opinion the advertisement is a bit of “cherry-picking” in which Hobby Lobby ( a privately held Company whose owners are Evangelical Christians) strives to assert that the United States of America is a Christian nation.
Notwithstanding that that there is no such thing as a “Christian nation” (see this from an evangelical scholar)…..
“Jonathan Merritt, an evangelical Christian writer and blogger for the Religion News Service, “……… arguing that conservative evangelicals shouldn’t call businesses “Christian” in the first place.
lied only to individuals. If the Bible is your ultimate guide, the only organization one might rightly term ‘Christian’ is a church. And this is only because a church in the New Testament is not a building or a business, but a collection of Christian individuals who have repented, believed on Christ, and are pursuing a life SUPREME COURT RULINGS “There is no dissonance in these [legal] declarations…These are not individual sayings, declarations of private persons: they are organic [legal, governmental] utterances; they speak the voice of the entire people…These, and many other matters which might be noticed, add a volume of unofficial declarations to the mass of organic utterances that this is a Christian nation.” Church of the Holy Trinity v. U.S., 1892” Unanimous Decision Declaring America a Christian Nation.
The Hobby Lobby folks do not acknowledge that the author of this opinion, Justice Harry Brewer wrote the following in 1905
But in what sense can it be called a Christian nation? Not in the sense that Christianity is the established religion or that people are in any matter compelled to support it. On the contrary, the Constitution specifically provides that 'Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof.' Neither is it Christian in the sense that all of its citizens are either in fact or name Christian. On the contrary, all religions have free scope within our borders. Numbers of our people profess other religions, and many reject all. Nor is it Christian in the sense that a profession of Christianity is a condition of holding office or otherwise engaging in public service, or essential to recognition either politically or socially. In fact, the government as a legal organization is independent of all religions. Nevertheless, we constantly speak of this republic as a Christian Nation--in fact, as the leading Christian Nation of the world. This popular use of the term certainly has significance. It is not a mere creation of the imagination. It is not a term of derision but has substantial basis--one which justifies its use. (Justice Brewer 1905 explanation)
In other words his comments of 1892 reflected that the USA was a Christian Nation “de facto”, but not “de jure”.