According to Ephesians 6:17, the only offensive weapon Christians have in standing against the devil is the word of God. Therefore, not believing that God's word is infallible and inerrant weakens the church.
This article shows that though some may have distorted the meaning of the word inerrant, the inerrancy of Scripture means that the Bible has no errors and is true. This is a good and accurate word to describe the infallible Word of God.
Is the Bible really inerrant? This article considers whether or not it is Reformed to affirm that the Bible is inerrant. It presents the case against inerrancy, and then observes whether the Reformed confessions affirm inerrancy, as well as the position of the Reformers themselves on this point.