Answer: Men (people) should observe rather than criticize. The more you observe and see the wiser you may be.
Or
Men (people) look to describe and visualize the world as they speak. With one tongue, they use to describe the beauty/evil of this world.
In general, most poems and quotes have many meanings. Charles Caleb Colton has unfortunately not explained his poem and what he wants the poem to mean or stand for.
