'Be Strong' in the Bible

Thus saith the LORD of hosts; Let your hands be strong, ye that hear in these days these words by the mouth of the prophets, which were 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 ye were a curse among the heathen, O house of Judah, and house of Israel; so will I save you, and ye shall be a blessing: fear not, but let your hands be strong.