Schools must teach the Excellency of the Christian Religion above all others, ancient or modern. -James Madison
I can find no attribution of this quote to James Madison anywhere. I have found a quote containing the phrase "Excellency of the Christian Religion" attributed to Benjamin Franklin. Franklin, a deist, did give lip service to Christianity, which seems to be a common trend with the founding fathers.
Whatever strikes at the root of Christianity tends to destroy civil government. -Supreme Court, 1811
This one was a tad confusing, but I'll try to give my best interpretation. This quote did not come from the Supreme Court of the United States. The quote came from the opinion of Judge Robert Raymond in 1729 when he was conducting a blasphemy trial on the King's Bench in the United Kingdom. Maybe that should be the Union Jack as the background image. In 1811 at the Supreme Court of New York in the case of "The People v. Ruggles", a man with the last name of Ruggles was convicted of blasphemy. On the attempt of an appeal, Justice James Kent used Raymond's opinion as part of his opinion as a reason why Ruggles' blasphemy conviction should stand.
If my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then will I hear from heaven and will forgive their sin and will heal their land. -2 Chronicles 7:14
This billboard may be misleading in content, but the verse 2 Chronicles 7:14 really does say that, so I have no comment.
[UPDATE, December 14, 2008]
"We recognize no Sovereign but God, and no King but Jesus." -John Adams
Yep. No proof that this was ever said. No citation has ever been provided. I can't even find a plausible explanation for this quote. Maybe one of our readers can.