Moshe returned to Hashem, and said, "Adonai, why have You brought harm to this people? Why have You sent me?"
The Ohr Hachaim explains this possuk as a legal discussion with Hashem. Moshe told Hashem, ‘why have you brought harm to this people’. Hashem told Moshe that He would harden Par’oh’s heart and he would not actually allow Klal Yisroel to leave. But He did not tell him that the subjugation would get worse. Obviously, the time had not yet arrived for their redemption. If so, why had Hashem sent Moshe to speak to Klal Yisroel?
The Ohr Hachaim adds that Hashem had shown Moshe that the redemption would not occur immediately and that more time was needed until Klal Yisroel had sorted the sparks of holiness that were trapped in Mitzrayim. Another twelve months were necessary.
Moshe told Hashem לָׂמָׂה הֲרֵעֹתָׂה לָׂעָׂם הַזֶה – why have you brought harm to this people? If Hashem thought that more suffering was in order, לָׂמָׂה זֶה שְלַחְתָׂנִּי – why have You sent me? Why did Hashem send Moshe to give Klal Yisroel false hope? The purpose of sending Moshe early was to remove the subjugation. Klal Yisroel would stay in Mitzrayim and redeem the holy sparks, but they would no longer have to work for the Mitzrim. But now that the subjugation had gotten worse, there was no purpose to the message sent to Klal Yisroel.
The Ohr Hachaim adds that Moshe used the word זֶּה which has a Gematriya of 12. Moshe was hinting to the twelve months that were added to their sojourn in Mitzrayim, even after he had been given the news that they would be redeemed. Moshe was worried that this extra work that Par’oh put on them would last the entire twelve months.
Another explanation offered by the Ohr Hachaim is based on the two different groups in Klal Yisroel. Not all of Klal Yisroel had to work in Mitzrayim; the tribe of Levi was exempt from work. Moshe was making two claims to Hashem.
As far as those who were subjugated are concerned, Moshe said לָׂמָׂה הֲרֵ עֹתָׂה לָׂעָׂם הַזֶה – why have you treated this nation so badly? They have to work so hard.
Regarding those who were not subjugated, those who did not need to work for all those years, Moshe said לָׂמָׂה זֶה שְלַחְתָׂנִּי – why have you sent me? Moshe meant that there was no purpose in his having been sent when they would still have to work.
