Until now we were learning about a Ahava Hateluya Bedovor - a love that is dependent on something, for example contemplating on the greatness of g-d and how he chose us.

In Perek 50 the Alter Rebbe speak about a Ahava Shaino Teluya Bedovor - an unconditional love that the Jewish people have to g-d, which is like the love betwen a husband and a wife.

In arousing that love the Alter Rebbe warns us that this love shouldn't lead us to Klois Hanefesh - where the Soul wants to leave the body to come closer and become 1 with g-d, rather we have to channel that love into learning Torah and keeping Mitzvos.