I came across this in my Bible reading today:
“Only be strong and very courageous, being careful to do according to all the law that Moses my servant commanded you. Do not turn from it to the right hand or to the left, that you may have good success wherever you go.8 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. 9 Have I not commanded you? Be strong and courageous. Do not be frightened, and do not be dismayed, for the Lord your God is with you wherever you go.” – Joshua 1:7-9
This is the transition of leadership moment from Moses to Joshua. Notice the familiar biblical pattern: that the Lord will be with his people, and with his leaders, wherever they go. That should instill confidence in us – our ultimate peace and security is guaranteed (Rom. 8). And he shows his mercy first before he asks our obedience, but you see that here too. I will be with you, he says, so obey what I say, follow my lead – as God always knows what is best for his people. And there is a way to do that too. He is calling upon Joshua to be engaged in the discipline in knowing God’s Word.
The Book of the Law here most likely refers to the Pentateuch, the book written by Moses chronicling God’s Law and redemptive history up to this point. He has the book, so he should consider the words carefully, letting the meditation on those words change the heart of Joshua. We are never spiritual robots, who by our faith just do what is right in God’s eyes, but instead we are called to participate in our own sanctification, by discipline, time, and effort. And that kind of work bears fruit – knowing God’s Word does help us to know what to do in life’s situations. So spend time reading and meditating on God’s Word!