'Be Strong' in the Bible

And the fourth kingdom shall be strong as iron: forasmuch as iron breaketh in pieces and subdueth everything, and as iron that breaketh all these, so shall it break in pieces and bruise.

and he said, Fear not, man greatly beloved; peace be unto thee, be strong, yea, be strong. And as he was speaking with me I was strengthened, and I said, Let my lord speak; for thou hast strengthened me.

And the king of the south, who is one of his princes, shall be strong; but another shall be stronger than he, and have dominion: his dominion shall be a great dominion.

And such as do wickedly against the covenant shall he pervert by flatteries; but the people that know their God shall be strong, and shall act.