It's not as if the New Testament writers came along and said, "The culmination of Old Testament books is more books, New Testament books." In some ways they thought instead of the culmination of Old Testament books being Christ himself, the word incarnate as the opening verses of Hebrews 1 put it. In the past God spoke to the fathers by the prophets, but in these last days he has spoken to us by his son and the son is revelation.

When Christians speak of the authority of Scripture, because Christians believe that this word, even though it's mediated through many different human authors, nevertheless is God breathed and is revealed by God and is utterly reliable and all that it says, with all of its different literary genres, it's trustworthy and without mistake or distortion. It is trustworthy and therefore, because it is from God it has God's authority.

God is absolutely sovereign, but his sovereignty never mitigates human responsibility.

When we suffer, there will sometimes be mystery. Will there also be faith? Yes, if our attention is focused more on the cross, and on the God of the cross, than on the suffering itself.

Make a mistake in the interpretation of one of Shakespeare’s plays, falsely scan a piece of Spenserian verse, and there is unlikely to be an entailment of eternal consequence; but we cannot lightly accept a similar laxity in the interpretation of Scripture. We are dealing with God’s thoughts: we are obligated to take the greatest pains to understand them truly and to explain them clearly.

At the end of the day, in brief summary: inerrancy is interested in the truthfulness of Scripture and it is a powerful way forcing people to think about that reliability that is God-given.

The important thing, Jesus is saying (in Matthew 5:33-37), is to tell the truth and keep one's pledges without insisting that a certain form of words must be used if it is to be binding. No oath is necessary for the truthful person... Their word is so reliable that nothing more than a statement is needed from them.