This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success.
Day and night is a strange amount of time to spend with one book. Not a quick read, not a Sunday glance — something closer to the way you'd turn over a hard decision or a piece of news you can't stop thinking about.
The verse isn't really selling meditation as a mood exercise, though. It's pointing at a chain: think about it constantly, then do what it says, then watch your way actually go somewhere. Most advice skips straight to the doing and wonders why it doesn't stick. This suggests the doing follows naturally once something has genuinely occupied your mind long enough to change how you see things.
You don't have to already believe this book is anything special to notice the logic. What you dwell on shapes what you do. The question worth asking is what's actually occupying your mind day and night right now, and whether it's leading anywhere good.
If you've never given a book of the Bible the kind of sustained attention you'd give a problem you actually cared about, that's an experiment worth trying.
A short video on this is coming soon — for now, read on.