"Be Strong" - to strengthen, to prevail, to harden, to be strong, to become strong, to be courageous, to be firm, grow firm, to be resolute, to be sore (Brown Driver & Briggs Hebrew Lexicon).
"Of Good Courage" - to be strong, to be alert, to be courageous, to be brave, to be stout, to be bold, to be solid, to be hard (Brown Driver & Briggs Hebrew Lexicon).
The source of their strength and courage is to be found in Jehovah God and their understanding that He is with them and will not leave them nor forsake them.
Here the encouragement of the Holy Spirit in the New Covenant: Let your conduct be without covetousness; be content with such things as you have. For He Himself has said, "I will never leave you nor forsake you." So we may boldly say: "The Lord is my helper; I will not fear. What can man do to me?" (Hebrews 13:5-6; NKJV)
Jason Cicero
