Rav Avrohom Chaim of Zlotchov zy”a (Sefer Orech L’Chaim) asks why the pasuk uses the words “V’haya eikev“ (and it will be, because you will...), rather than simply saying: “If you will obey these laws...“
He answers that the pasuk is using the word “eikev“ to hint to the “ikvesah d’meshicha“, the time period immediately before the arrival of Moshiach. At this time, the world will become full of falsehood and people will be shamelessly running after empty desires. We will be unable to protest against sinners because they will be the ones in leadership positions.
If a person follows the proper path even during this difficult time and obeys all of the mitzvos of the Torah, he will be rewarded greatly and he will be very appreciated and valued by Hashem. This is why the pasuk uses the word “v’haya”, which connotes joy, as a person who follows the Torah even in the time of “eikev” creates much joy for Hashem.
