If I were to give you the shortest answer possible without reading any replies it would be this:It is not true. They are not sufficient, and I honestly believe someone has to condition you to believe that it is. Every book in the Bible was written at least 1800 years ago, in societies and cultures that faced different issues than we do today, and every attempt to suggest that the Bible can address every possible issue and problem is an attempt to ascribe supernatural powers to it that, in my opinion, border on the exact kind of idolatry it teaches against. To think that a book (yes, any book) can answer all your questions and solve all your problems, effectively meaning you do not need to seek out God is to allow this book to replace God. Now having given that some thought, I may decide to write further on this subject.