Only be strong and very courageous, to observe to do according to all the law, which Moses my servant commanded you: don't turn from it to the right hand or to the left, that you may have good success wherever you go.
Now God is saying, "Look keep the law, don't deviate from it, for it is by this observing it day and night, meditating in it, thus thou shalt make thy way prosperous, thus you will have good success."