Moses instructs the people of Israel: When you enter the land that G-d is giving to you as your eternal heritage, and you settle it and cultivate it, bring the first-ripened fruits (bikkurim) of your orchard to the Holy Temple, and declare your gratitude for all that G-d has done for you.
Our Parshah also includes the laws of the tithes given to the Levites and to the poor, and detailed instructions on how to proclaim the blessings and the curses on Mount Grizzim and Mount Ebal -- as discussed in the beginning of the Parshah of Re'ei. Moses reminds the people that they are G-d's chosen people, and that they, in turn, have chosen G-d.
The latter part of Ki Tavo consists of the Tochachah ("Rebuke"). After listing the blessings with which G-d will reward the people when they follow the laws of the Torah, Moses gives a long, harsh account of the bad things -- illness, famine, poverty and exile -- that shall befall them if they abandon G-d's commandments.
Moses concludes by telling the people that only today, forty years after their birth as a people, have they attained "a heart to know, eyes to see, and ears to hear."