Joshua 1:8

This book of the Law, as it had been written by Moses and delivered into the hands of the priests, Deuteronomy 31:26, shall not depart out of thy mouth, he should teach it, study it, discuss it; but thou shalt meditate therein day and night, trying to penetrate ever more deeply into its scope and meaning, and thus becoming qualified to speak more clearly, pointedly, and powerfully to the people, that thou mayest observe to do according to all that is written therein, namely, in the thoughts of the heart and in the deeds of the hands; for then thou shall make thy way prosperous, make headway on the path of duty before him, and then thou shalt have good success, because of the application of practical wisdom given by the Lord. The Lord now summarizes His charge to Joshua, introducing it by a rhetorical question for the sake of greater effect.