'Be Strong' in the Bible

Then you shall prosper, if you take heed to fulfil the statutes and judgments with which Jehovah charged Moses, concerning Israel. Be strong and of good courage. Do not fear, nor be dismayed.

Take heed now, for Jehovah has chosen you to build a house for the sanctuary. Be strong and do it.

And David said to Solomon his son, Be strong and of good courage, and do it. Do not fear, nor be dismayed, for Jehovah God, my God, will be with you. He will not fail you nor leave you until you have finished all the work for the service of the house of Jehovah.