'Good Courage' in the Bible

Be of good courage, and let us fight valiantly for our people, and for the cities of our God: and let the LORD do that which is good in his sight.

Then shall you prosper, if you take heed to fulfill the statutes and judgments which the LORD charged Moses with concerning Israel: be strong, and of good courage; dread not, nor be dismayed.

And David said to Solomon his son, Be strong and of good courage, and do it: fear not, nor be dismayed: for the LORD God, even my God, will be with you; he will not fail you, nor forsake you, until you have finished all the work for the service of the house of the LORD.