'Be Strong' in the Bible

"I am going the way of all the earth. You be strong therefore, and show yourself a man;

The servants of the king of Syria said to him, "Their god is a god of the hills; therefore they were stronger than we. But let us fight against them in the plain, and surely we shall be stronger than they.

Muster an army, like the army that you have lost, horse for horse, and chariot for chariot. We will fight against them in the plain, and surely we will be stronger than them." He listened to their voice, and did so.