Janet Greenleaf

“When the government puts its imprimatur on a particular religion it conveys a message of exclusion to all those who do not adhere to the favored beliefs. A government cannot be premised on the belief that all persons are created equal when it asserts that God prefers some.”
― Harry A. Blackmun

“The purpose of separation of church and state is to keep forever from these shores the ceaseless strife that has soaked the soil of Europe in blood for centuries.

[Letter objecting to the use of government land for churches, 1803]”
― James Madison

“...legitimate powers of government reach actions only, & not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should 'make no law respecting an establishment of religion, or prohibiting the free exercise thereof,' thus building a wall of separation between Church & State. Adhering to this expression of the supreme will of the nation in behalf of the rights of conscience, I shall see with sincere satisfaction the progress of those sentiments which tend to restore to man all his natural rights, convinced he has no natural right in opposition to his social duties.”
― Thomas Jefferson, Letters of Thomas Jefferson

“Almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so.”
― Robert A. Heinlein