We know from Chazal how important it is to study Maaseh Avot, the lives of the Avot (forefathers) and all their Avodah (service) that they did. The person is required to study it. It’s a very, very important part of our Avodat Hashem (service of God) to study the Avot. Rabbi Kotler says that if a person learns and studies, he knows all of the Torah, but he never was... Chazal tell us that this person is an am ha'aretz: he doesn't know how to practically apply the information and the knowledge that he learns.
If he's not, Rabbi Kotler says that in Hilchot (laws of), in Hilchot is learning the Parashah of the Avot. So a person who doesn't study these Parashot properly can never reach the place that he needs to reach in Avodat Hashem. Avodat Hashem needs what we call a Dugma Ishit, because the Torah has to be lived through a personality. It has to be lived in real life, and by seeing it practiced and by observing it, one can kind of understand how to understand it on a deeper level and apply it to his own life.
We know that at the end of Masechet Sotah, it says what happened when many, many great Rabbis passed away. For example, it says that when Rabbi HaKadosh passed away, the middah (character trait) of Anavah (humility) was batel (ceased), and various different middot that we speak about over there. Why is the middah of Anavah batel just because Rabbi passed away and he was a great Anav (a humble person)? So the commentaries explain: It is because you can learn about Anavah in a sefer, and you can think that you understand humility, but you don't really comprehend it unless you have humility.