This is an interesting quote from Prof AC Grayling a popular humanist and editor of an Atheistic Bible called the 'Good Book'. I'm not sure why it's called that. Survival of the fittest doesn't seem like a good message in my eyes. Anyway, I reckon what Grayling has articulated is a very popular view of scripture. Most people that I speak to think the Bible is simply a book of rules and stories that were written to help us live morally. The Bible clearly contains lots of commands. But these rules weren't primarily written to change our behaviour.
The Bible was written firstly to show us how weak we are to keep God's commands. For example in Galatians 3:22 the Apostle Paul is teaching a church in modern day Turkey, he writes 'the scripture has confined all under sin'. His point is that after reading the old testament properly we will became more aware of our sin. The law confines us to sin because the more we look at God's law, the more we see his perfect standards, the more we become convinced the we are unable to obey Him perfectly. If we stop reading there the Christians message sounds quite depressing- full of guilt and despair...
The good news is the Bible also wants us to see that God has kept His own commandments on our behalf. See Galatians 3:19: 'the law was our tutor to bring us to Christ, that we might be justified by faith'. So the law brings us to Christ. In other words, the law (which reveals our sin) points us and connects us to the God-man, Jesus Christ, who died for our sin. Jesus also kept the law perfectly as if He were us. The result is 'justification by faith'. Imagine God in a crown court. He looks at you a disobedient sinner, one who has never honoured Him as He deserves. You think the verdict is going to be 'guilty'. But God pronounces you 'righteous'. Righteous is much much more than not guilty. Being declared 'not guilty' is brilliant because it means that you've never disobeyed. 'Righteous' on the other hand means constant perfect obedience. it speaks of someone who has never done anything wrong and always done what was right. It speaks of Jesus.
This justification is 'by faith', faith in Christ. What I'm saying is that the justification is not automatic. It's dependent on you trusting that God will freely give it to you. The declaration of 'righteous' is the declaration that Christ should have heard for His obedience. Instead of hearing 'righteous' on the cross He heard the word 'guilty'. With the guilt of my sin He was punished to liberate anyone who trusts.
Understanding the Bible properly brings transformation.