Proverbs 30:5 says that every word of God is true. John 10:35 says that Scripture cannot be broken. Psalm 12:6 says the words of the Lord are pure.  Obviously, if God is perfect, and God has spoken, it would naturally mean that all that was written in the inspired documents is without error.  Infallibility is related to inerrancy--but means more powerfully:  not able to be wrong.