Aliya Summary: The male firstborn of kosher cattle must be consecrated and given to the Kohen to eat. If the animal is unblemished it is first offered as a sacrifice in the Temple. The Torah reading concludes with a discussion regarding the three festivals: Passover, Shavuot, and Sukkot. In addition to some laws regarding each of these festivals individually, we are commanded to rejoice during the festivals and all males must be in attendance in the Holy Temple during these holidays.
Being commanded to rejoice seems like an oxymoron, but just like the commandment to love G-d, and others, these are what’s known as the “duties of the heart”, which is the result of proper determinations by the mind.