Joshua 1:6-8

6 Be strong and of a good courage; for thou shalt cause this people to inherit the land as an inheritance, which I swore unto their fathers to give them.

7 Only be thou strong and very courageous that thou mayest keep and do according to all the law, which Moses my servant commanded thee; turn not from it [to] the right hand or [to] the left that thou may be prospered in all the things that thou doest.

8 This book of the law shall not depart out of thy mouth, but thou shalt meditate therein day and night that thou may keep and do according to all that is written therein; for then thou shalt make thy way to prosper, and then thou shalt understand everything.