Parshat בא has a total of twenty laws in it. Nine are positive and eleven are negative commandments. Most of these laws have to do with the offering of the Pesach sacrifice, while others deal with some of the rules related to the preparation of the Pesach holiday. They discuss the prohibition of having Chametz in our possession and the prohibition of eating Chametz.
The של״ה הקודש takes this Parsha as his opportunity to emphasize the importance of studying those laws that have no relevance in today's world. Even though we pray and believe that we will one day offer the קרבן פסח, the details as to how to prepare it, do not yet affect us.
The point of the של״ה הקודש is that when we diligently learn such laws, we are rewarded as if we observed them.
My late brother in-law Rav Yair זצ״ל, (his Yahrtzeit is in the month of שבט) once told me when I was eighteen years old, how important it was to study all of the rules related to all of the קרבנות. Not only is there great reward in such study, but it is an indication that one is truly learning Torah לשמה, for the sake of Heaven.
From time to time, we need to be reminded of this.