This book of the law shall not depart from thy mouth; and thou shalt meditate upon it day and night, that thou mayest take heed to do according to all that is written therein; for then shalt thou have good success in thy ways, and then shalt thou prosper.
God's charge to Joshua comes as he takes over from Moses and faces a land full of enemies. The strength God offers him is tied to one book. The instruction is not to read now and then, but to keep Scripture in mouth and mind day and night. A promise comes with it, and that promise raises a question: what do "prosperous" and "good success" mean for someone in God's service?
Strength shown in obedience
Courage here has a purpose: doing what is written. One writer notes that God promised His power, but it would show itself in one particular way.
They were to show strength and courage, and to show it in obedience. Obedience is where strength shows itself. So by obeying, they would beat their enemies. The Lord's power would be there, but they were to show their strength in obedience. Now the world is all against us. It says, "you are fools for all your trouble." That is what it says if we keep obeying the word simply, instead of following the world's plain good sense. There is no wisdom like faith.
Meditation aimed at doing
The verse gives meditation a stated goal — being careful to do all that is written. That goal exposes why we usually open the Bible.
There must then be, besides divine energy, diligent care to take in the thoughts of God. He says: meditate on it so that you obey. Is that our aim when we study the word of God? Often we like to read in order to learn, which is a good thing in itself. At other times we read so that we can pass it on to others, which is also excellent in its place. But do we read it in order to obey? If it were so, how it would change the whole current of Christians' lives!
Knowing much and doing nothing is not a neutral position:
Meditation and practice, like two sisters, must go hand in hand. The end of meditation is action. Those who meditate on God's law and do not do it are no better than the devil; he knows much, but is still a devil.
Day and night
Set "day and night" beside how most of us treat the Bible.
Some Christians read a chapter every morning — sometimes only a verse! — as a charm to protect them through the day. Is that meditating day and night on the word of God? "What about our occupations?" you say. Well, let me ask you in return. In the middle of your work, is it God's word that feeds you? He gave that word for your soul's enjoyment, and to guide you in the path of Christ. That is the way to prosper and have good success.
The man receiving this command was not a man with spare hours:
This was a famous military commander, and he carried great responsibilities. Even so, he had to make time not only to read God's word, but to meditate on it. It was vital to his prosperity in every way. Do we "make time" for reading and meditation?
What meditation does to a person
Beyond telling us God's will, dwelling on the word changes the way we see everything.
This meditation on God's word, of course, makes us know His will. But it does a great deal more. It gives the heart a settled delight in what God reveals, in what He delights in. We acquire His way of thinking of things — the true and divine way, not the way of this world's empty show. Our own hearts are formed by this divine and blessed understanding of things. What a light this is! It shows how empty this world really is.
It also produces a different kind of person than study alone does:
No hour is better spent than the hour a Christian spends alone with God over His word. There he weighs God's thoughts in God's presence. A book-learned Christian and a Spirit-taught Christian are very different. A person may know the truth of the word from reading or teaching, and still hardly ever meditate on it.
Prosperity and good success
The promise is real, but the route to it is what most people abandon.
The success is great indeed, and it is certain for those who follow the rule laid down long ago to Joshua... Yet how much more often people expect success from a flexible, worldly wisdom than from close and steady loyalty to the Word of God!
Joshua had only the law of Moses. Christians have more:
The Book of the Law was to be Joshua's meditation day and night, so that he might do all that was written in it. We today need, not only the Old Testament, but the whole truth of the New Testament if we are to have spiritual prosperity and success.
Summary
- Obedience first. God supplies the power, but a believer shows strength by obeying His word, not apart from it.
- Obedience needs feeding. Meditation takes God's thoughts in. Its stated aim is doing what is written, not gathering material to teach others.
- Feeding needs time. A commander with an army to lead was told to make room for the word day and night; a verse read as a morning charm is not that.
- Time reshapes the man. Hours alone with God over Scripture shape how we think. They show up the emptiness of the world, and leave us humble, not just informed.
- The reshaped man prospers. God promises success, but to steady loyalty to His word, not to flexible worldly wisdom. For us that word now includes the whole New Testament.