In the first chapter of Plantinga's Engaging God's World, the distinction of hope and longing are brought to attention. He discusses how longing is a part of hope, along with imagination, faith, and desire. As humans, we are restless for hope and we desire for it to come.
However, in our hope and longing, our desires must be lawful and approving in God's sight. It when we hope and long for our Savior, that God is pleased. Through Jesus and His death and resurrection, hope is renewed and found everlasting. All other earthly desires and lust can not offer peace or new life. We must long and hope for redemption in Jesus Christ.
Plantinga later discusses our hope for shalom. Shalom means peace, and in our search for shalom, we must never forget that it is only through God that we can achieve perfect shalom. In finding shalom personally, it is our duty, as Christians, to spread it to the community and to the world.