J I Packer has commented well on this.
'Let us read the Bible then — if we can. But can we? The truth is that many of us have lost the ability to read the Bible. When we open our Bibles, we do so in a frame of mind which forms an insuperable barrier to our ever reading it at all. This may sound startling, but it is not hard to show that it is true.
When you sit down to any other book, you treat it as a unit. You look for the plot, or the main thread of the argument, and follow it through to the end. You let the author's mind lead yours. Whether or not you allow yourself to "dip" before settling down to the book properly, you know that you will not have understood it till you have been through it from start to finish, and if it is a book that you want to understand you set aside time to read it in full. But when we come to Holy Scripture, our behaviour is different. In the first place, we are in the habit of not treating it as a book — a unit — at all, but simply as a collection of separate stories and sayings. We take it for granted before we look at the text that the burden of them — or, at least, of as many of them as affect us — is either moral advice or comfort for those in trouble. So we read them (when we do) in small doses, a few verses at a time. We do not go through individual books, let alone the two complete Testaments, as a single whole. We browse through the rich old Jacobean periods of the Authorised Version, waiting for something to strike us. When the words bring to our minds a soothing thought or a pleasant picture, we feel that the Bible has done its job for us. It seems that the Bible is for us not a book, but a collection of beautiful and suggestive snippets, and it is as such that we use it. The result is that we never read the Bible at all. We take it for granted that we are handling Holy Writ in the truly religious way; but in truth, our use of it is more than a little superstitious. It is the way of natural religiosity, perhaps, but not of true religion.'
How do we read the Bible? Do we read it as a 'dip and pick'? Do we read it as a 'promise box' looking for a 'pick-me-up' to get me through the day? Or do we seek to read it like we read any book, as a unit, with a view to grasping its big picture? Only by reading it in this latter way is it possible to gain a mature understanding of our faith.