'Be Strong' in the Bible

For then thou shalt prosper: If thou shalt be diligent to do the ordinances and laws which the LORD charged Moses with, to deliver to Israel. Pluck up thine heart and be strong, dread not, nor be discouraged.

Take heed now, for the LORD hath chosen thee, to build a house of thy sanctuary. Be strong and do it."

And David said to Solomon his son, "Harden thyself and be strong and do it. Fear not, nor let thine heart discourage thee. For the LORD my God is with thee, and shall not leave thee nor forsake thee, until thou hast finished all the work that must serve for the house of the LORD.