Bible reference (Old Testament) ~ 1Chronicles 28:19-21 and Joshua 1:8-9 

King David was transfering his reign over to his son Solomon. He was preparing Solomon to build the temple for God. When he gave him instructions he used similar encouraging words that God told Joshua and the Israelites as they were about to go in and conquer the land God had promised them. 

Here is an interesting note. Moses was the leader of God’s people before Joshua. God told Moses he would not enter the Promised land so he gave Joshua the leadership position. God told David he would not build His temple so David gave the instructions to his son. 

1 Chronicles 28

19 “Every part of this plan,” David told Solomon, “was given to me in writing from the hand of the Lord.” 20 Then David continued, “Be strong and courageous, and do the work. Don’t be afraid or discouraged, for the Lord God, my God, is with you. He will not fail you or forsake you. He will see to it that all the work related to the Temple of the Lord is finished correctly. 21 The various divisions of priests and Levites will serve in the Temple of God. Others with skills of every kind will volunteer, and the officials and the entire nation are at your command.”

Joshua 1:8-9

8 Study this Book of Instruction continually. Meditate on it day and night so you will be sure to obey everything written in it. Only then will you prosper and succeed in all you do. 9 This is my command—be strong and courageous! Do not be afraid or discouraged. For the Lord your God is with you wherever you go.”