II Samuel 23:10 He arose, and smote the Philistines until his hand was weary, and his hand clave unto the sword: and the LORD wrought a great victory that day; and the people returned after him only to spoil.
Hold on to your sword. You might get tired in the work but never of the work. Hold on to your sword and he will win a great victory. Use all your strength. Work until you are tired.