Adding to Scripture is forbidden by Scripture regardless of how deep we think the thought is. Scriptural additions could number in the millions, especially with all the man-made systems, formularies, books, and church councils that have added their own thoughts to Scripture. For brevity however, here is one example at this link. Another example is this quote from Samuel Chadwick, mentor of Leonard Ravenhill:
“The one concern of the devil is to keep Christians from praying. He fears nothing from prayerless studies, prayerless work, and prayerless religion. He laughs at our toil, mocks at our wisdom, but trembles when we pray.”
Where do you find this in Scripture? No where.
Prayer is important. It is our way of talking to GOD. The Bible is also important. It is GOD’s way of talking to us. Which is more important? While a quote like the one above may be sincere, it is an ADDITION to Scripture to say that “THE ONE CONCERN of the devil is to keep Christians from praying”.
“For I testify unto every man that hears the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book: And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book.”
– Revelation 22:18-19