Why is this article inserted?

To show us that our happiness is not situated on the earth. This serves a two-fold end. We are to learn to pass through this world as though it were a foreign country, treating lightly all earthly things and declining to set our hearts on them. Secondly, we are not to lose courage, no matter how much we fail to perceive as yet the fruit of the grace which the Lord has wrought for us in Jesus Christ, but wait patiently until the time of revelation.