The four kosos represent the four lashonos of geula that are unique to Pesach night. The third kos is the kos that we drink for Birchas HaMazon. But Birchas HaMazon always has a kos. Why is this considered one of the four kosos of freedom on Pesach?
A person can have freedom from many things and feel really independent. However he says there is one freedom that is harder to achieve than others. That is freedom from believing that your efforts bring you Parnasa. When it comes to health, children, and many other areas, with a little hard work and experience we manage to teach ourselves that it all comes from Hashem. However when it comes to our livelihood we more often than not hide behind the guise of “Hishtadlus” because we are just not sure that Hashem really grasps the business world.
When a person can say with a full mouth and whole heart the words, “Hazan Es HaOlam Kulo Bituvo B’Chen B’Chesed…Hu Nosen Lechem”; all our wealth and earnings come only from Hashem with kindness and mercy, through absolutely no help of our own, only then is a person truly free. At that point he can raise his kos and celebrate the freedom of Mitzrayim, the freedom to serve Hashem with his whole heart.
