You answered me, and said, "The thing which you have spoken is good to do”.
Chazal tell us that Klal Yisroel failed at their test. They should have answered back, “From whom is it better to receive, the teacher or the disciple? We wish to learn directly from Moshe Rabbeinu; we don’t want to learn from a pupil of yours. You, Moshe, who worked so hard for us, are a better teacher than any pupil of yours.” This reads the possuk as an admonishment to Klal Yisroel for willingly relinquishing their connection to Moshe Rabbeinu.
The Ohr Hachaim suggests that another explanation could consider it praise for Klal Yisroel. Although it would have been better for Klal Yisroel to learn directly from Moshe Rabbeinu, they wished to protect Moshe’s health and well-being and gave up their own benefits for Moshe’s. This explains the different expressions used by the possuk. First, it says וַתֹּאמְרוּ, which is a soft language on the part of Moshe Rabbeinu, but he told them that they דִבַּרְתִּם - you spoke strongly. They said that it would be difficult for them to accept his suggestion, but they took it for Moshe’s benefit.
It is possible that Moshe meant to send a double message. Some of Klal Yisroel were complainers who tried to cause Moshe Rabbeinu as much trouble as possible. Others were great people who wished for Moshe’s benefit. Each person knew to which group he belonged. Moshe was giving both messages at the same time, telling each one what he needed to hear.
