'Be Strong' in the Bible

Thus says the LORD of hosts; Let your hands be strong, you that hear in these days these words by the mouth of the prophets, who were there in the day that the foundation of the house of the LORD of hosts was laid, that the temple might be built.

And it shall come to pass, that as you were a curse among the nations, O house of Judah, and house of Israel; so will I save you, and you shall be a blessing: fear not, but let your hands be strong.