Meditate on The Word

Joshua was commanded to be strong and very courageous, being careful to obey all the Law of Moses. This command is based on God’s power through His Word. This is a stronger exhortation, indicating that greater strength of character would be required to obey God’s Word faithfully and fully than to win military battles! The emphasis in these verses is clearly on a written body of truth. Many critics argue that the Scriptures did not appear in written form until several centuries later but here is a clear reference to an authoritative Book of the Law. To enjoy prosperity and be… successful in the Conquest of Canaan Joshua was to do three things
with regard to the Scriptures:

(a) The Law was not to depart from his mouth; he was to talk about it (Deuteronomy 6:7);

(b) He was to meditate on it day and night,to think about it (read Psalm 1:2; Psalm 119:97);