'Be Strong' in the Bible

Be strong, O Philistines, be men! Do not be servants to the Hebrews as they have been to you: go forward to the fight without fear.

And Saul said to David, Here is my oldest daughter Merab, whom I will give you for your wife: only be strong for me, fighting in the Lord's wars. For Saul said, Let it not be through me that his fate comes to him, but through the Philistines.