7 Only be strong and very courageous, that thou mayest take heed to do according to all the law that Moses my servant commanded thee. Turn not from it to the right or to the left, that thou mayest prosper whithersoever thou goest. 8 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.
Matthew Henry's Commentary on Joshua 1:7-8
Commentary on Joshua 1:5-9
(Read Joshua 1:5-9)
Joshua is to make the law of God his rule. He is charged to meditate therein day and night, that he might understand it. Whatever affairs of this world we have to mind, we must not neglect the one thing needful. All his orders to the people, and his judgments, must be according to the law of God. Joshua must himself be under command; no man's dignity or dominion sets him above the law of God. He is to encourage himself with the promise and presence of God. Let not the sense of thine own infirmities dishearten thee; God is all-sufficient. I have commanded, called, and commissioned thee to do it, and will be sure to bear thee out in it. When we are in the way of duty, we have reason to be strong and very bold. Our Lord Jesus, as Joshua here, was borne up under his sufferings by a regard to the will of God, and the commandment from his Father.