'Be Strong' in the Bible

Now therefore let your hands be strong, and be ye valiant; for Saul your lord is dead, and also the house of Judah have anointed me king over them.

And Ahithophel said unto Absalom, Go in unto thy father's concubines, that he hath left to keep the house; and all Israel will hear that thou art abhorred of thy father: then will the hands of all that are with thee be strong.