Only the Bible is the inspired word of God given to man.  We see this in 2 Timothy 3:16: “All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness.”  Paul also states that the gospel is a revelation of Jesus Christ: “The gospel I preached is not something that man made up … I received it by revelation from Jesus Christ.” (Galatians 1:11-12)  There are many books and writings from other religions, but they are not the inspired word of God.  There are also many Christian books and literature, but they should not be considered inspired directly by God.  

Any other books or words should be tested against the scriptures to see if what they state is true – “Prove all things; hold fast that which is good.” (1 Thessalonians 5:21)  We are told to test the spirits to see if they are from God (1 John 4:1-3).  The Bereans “examined the Scriptures every day to see if what Paul said was true.” (Acts 17:11)  We should follow the example of the Bereans – any preaching, words, or writings from outside the Bible should be tested against the scriptures in the Bible to see if they are true.