According to Daniel, this verse describes a really strong kingdom that is tough like iron. Just like iron can smash and break things, this kingdom will be very powerful and able to control everything.
Daniel 2:40: And the fourth kingdom shall be strong as iron: forasmuch as iron breaketh in pieces and subdueth all [things]: and as iron that breaketh all these, shall it break in pieces and bruise.
Daniel 2:40 describes the fourth kingdom as breaking and consuming all others, which contrasts with Matthew 5:5's depiction of the meek inheriting the earth, emphasizing gentleness and peace over conquest.
Matthew 5:5: Blessed [are] the meek: for they shall inherit the earth.