The documents may not mention to Bible.
Interesting "slight of tongue" the way you phrase that. It's not a matter of may not. They don't. Had the founding fathers wanted to mention the Bible in the U.S. Constitution and or the Bill Of Rights they would have. Obviously they saw important reasons to not include any reference to the Bible in the U.S. Constitution and or the Bill Of Rights.
Those documents are what the U.S. laws are based on. Now, if you want argue that for more than a century politicians in congress have mostly ignored the U.S. Constitution and Bill Of Rights, I can agree with that. In that case, how they have trashed the constitution is dishonest and wrought with fraud. If you want to argue that for several decades politicians in congress have mostly ignored the U.S. Constitution and Bill Of Rights in favor of using the Bible as their guide, have at it. Don't expect me to agree with you though.