The Power of Joy to Forget Olam Hazeh

The Kotzker Rebbe zy”a (Sefer Ohel Torah) makes note of the fact that the word “v’haya“ always connotes joy and asks how it could be used in this pasuk, which is speaking about forgetting Hashem.

He answers that we see from this pasuk that the power of joy is so great that one who is happy can come to forget even the most important things. One who is happy in the wrong way can even forget that he must praise Hashem and thank Him for every breath he takes. One can thus make a kal v’chomer and discern that if he abandons his evil ways and serves Hashem with joy, he certainly will forget all of the emptiness of this world and he will be able to focus fully on avodas Hashem.