An age old problem, and the same battle Paul fought that still goes on today. Seems everywhere you turn, someone is either adding to or watering down the Gospel that was given to us by our Lord and Savior through Paul the apostle. That's why we should study daily, God's Word, less we be fooled.
"Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth." - 2 Timothy 2:15
"All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works." - 2 Timothy 3:16-17