Parshat Eikev states (8:5): “Ki Ka’asher Yeyaser Ish Et Beno, Hashem Elokecha Meyasrecha,” “Just like a father is ‘Meyaser’ his son, Hashem, your God, is ‘Meyaser’ you.” What exactly does Meyaser mean?
Artscroll translates Meyaser as “chastise.” This would mean that the word Meyaser is related to Yisurin, trials and travails. This is based on Ramban, who states that through these trials and travails, we will better appreciate what we do have. Just as Hashem caused us various difficulties in the desert to make us better appreciate Eretz Yisrael, so too we must realize that any difficulties we encounter in life have some ultimate purpose as well.
The Sforno takes a somewhat different approach. He relates Meyaser to Mussar, rebuke. Just as a father rebukes his son in order to help him become a better person, Hashem rebukes us in order to make us better people. The translation in the JPS Tanach takes this approach, translating Meyaser as “discipline.” This translation would fit with a different use of the root of Meyaser in Parshat Vaetchanan. There the Torah says (Devarim 4:36): “Min Hashamayim Hishmiacha Et Kolo LeYasreka,” “From heaven, He let you hear His voice to be ‘Meyaser’ you.” In that Pasuk, the translation given by Ramban does not fit very well; Hashem did not let us hear His voice to cause us pain or force us through difficulty. The translation as “rebuke” fits better into that Pasuk. The Sforno in fact says in his commentary to Devarim 4:36 that Hashem rebuked us to make us better and to raise us to the level of prophecy.
Rav Hirsch relates the root of Meyaser (Yud Samech Reish) to the root of the word “Vayitzer,” “And He formed,” used in Parshat Bereishit (Yud Tzadi Reish), referring to how Hashem created and formed Adam from the Earth. Rav Hirsch comments that both roots mean taking something loose and unformed and giving it shape and character. The definition of Meyaser is that Hashem forms us and give us direction, just as a father forms and directs his child. Mussar helps us take our potential and turn it into real achievements.
Rav Tzvi Hirsch Weinreb combines these approaches. Hashem does not give us trials and tribulations to cause us pain, Chas VeShalom. The point is to direct us from whatever incorrect path we were on, and to move us onto a proper path. By giving us Yisurin, Hashem is in effect also giving us Mussar. Whenever we suffer difficulties, we must remember that Hashem is really sending us a message that we have to take Mussar and change our direction.