'World' in the Bible

What profit has a man if he gets all the world with the loss of his life?

Who will not get a hundred times as much now in this time, houses, and brothers, and sisters, and mothers, and children, and land--though with great troubles; and, in the world to come, eternal life.

For in those days there will be sorrow, such as there has not been from the time when God made the world till now, and will not ever be again.

And he said to them, Go into all the world, and give the good news to everyone.