Exodus 19:8

"Moshe brought the words of the people..." - On the next day which was the third day, as he went up at daybreak. And did Moshe need to answer God [i. e. did God not already know what the people said]? Rather, the text comes to teach us proper etiquette, that he did not say 'the one who sent me already knows and I do not need to answer him.'

And all the people responded together, and said, All that the Lord hath spoken we will do. And Mosheh carried back the words of the people before the Lord.

VAYASHEV MOSHEH’ THE WORDS OF THE PEOPLE UNTO THE ETERNAL. This means that Moses returned in the sense of “returning,” and not of “reporting”: “he returned to G-d with the words of the people.” “And there was no need to mention that ‘he went up to the mountain,’ since Scripture speaks here briefly” (Ibn Ezra). before Him to the mountain with the people’s answer. Now everything is revealed to Him, and He did not inquire of him, “What did this people answer you?” It is similar in meaning to the verse: And the Eternal heard the voice of your words, when ye spoke unto me. And when Moses came before Him, the Holy One, blessed be He, said, Lo, I come unto thee in a thick cloud, that the people may hear when I speak with thee, and may also believe thee forever. Then Moses said before Him,, i.e., the words they had said, “Master of the universe, etc.” On the significance of this interpretation of Ramban, see further, Note 186. “Master of the universe, your children are people of faith, and they accept upon themselves whatever You will speak.”
The above usage [of the word vayashev as meaning “returning” or “coming back”] is also found in the verse, ‘vayashivu’ unto them word… and they showed them the fruit of the Land, which means: “They [i.e., the spies] came back to them with the things which they saw.” [It cannot mean that “they reported” to them], for afterwards Scripture says there, And they told him, and said., Verse 27. [Hence, vayashivu in the preceding verse must mean that “they came back” with the things they had seen.] here means that “Moses came back” with the words of the people to G-d. Actually, however, as Ramban continues to explain, he did not report them, as everything was revealed to Him. This differs with Ibn Ezra’s interpretation, as explained in the following note. There is thus no need for Rabbi Abraham ibn Ezra’s interpretation on this point., why does it say again at the end of Verse 9, and Moses told the words of the people unto the Eternal? To remove this difficulty, Ibn Ezra said that vayageid Mosheh (and Moses told) in Verse 9 means that “Moses had already told the words of the people to G-d.” It is thus clear that Ibn Ezra explained vayashev Mosheh in Verse 8 as meaning that Moses “reported” the words of the people to G-d. Hence, Ibn Ezra’s difficulty and his forced solution. Ramban, however, explains vayashev Mosheh as meaning that Moses returned to G-d to report these words. Actually, there was no need to report them, as explained above. Then G-d said to him, Lo, I come unto thee, etc. (Verse 9), and finally vayageid Mosheh: Moses told these words to G-d, i.e., that His children are men of faith and that they accept upon themselves whatever He will speak. “There is thus no need for Ibn Ezra’s interpretation on this point,” as Ramban succinctly puts it.

AND MOSHE BROUGHT BACK THE PEOPLE’S WORDS TO ADONAI. On the next day, as it explains (v.9), "And Adonai said to Moshe, 'I will come to you in a thick cloud, etc.'"

And then (ibid.) "Then Moshe reported the people’s words to Adonai";

that is "And Moshe brought back, etc." It states the general and then goes back and supplies details. ... This is what Moshe said to the Holy One, blessed be He: "Already from yesterday, they took it upon themselves to do what You would command them." Similarly (Lev. 9:24 - 10:2), "Fire came forth from before Adonai and consumed the burnt offering" and meanwhile, "Now Aharon’s sons Nadav and Avihu each took, etc." "And fire came forth from Adonai" and reached Nadav and Avihu before the gold altar, which was in the sanctuary, when they brought alien fire on it, and it burned them, and went outside and consumed the burnt offering on the brass altar, which was in the courtyard outside the sanctuary. And similarly in in the Book of Judges in the section about Michah (Jud. 17:3-4): "He returned the eleven hundred shekels of silver to his mother; but his mother said, 'I herewith consecrate the silver to Adonai, etc.' He gave the silver back to his mother." In the beginning, the verse says, "He returned the ... silver to his mother," and afterwards it explains how, "but his mother said, etc. He gave the silver back to his mother."

וישב משה את דברי העם, Moses relayed to G’d what he had understood as being the people’s reactions. What he had understood was that they did not doubt his status as a prophet at all.

וישב משה, “Moses brought back the reply, etc.” the reason why in verse eight the Torah uses the term וישב, for Moses bringing back the people’s answer, whereas in verse nine the word ויגד, “he told,” was chosen by the Torah is that when Moses began to tell G–d the people’s reaction, G–d interrupted him by saying that He wanted him to wait as He wished to speak to him some more. When G–d had completed speaking with Moses, Moses resumed telling Him about the people’s reaction. In the tractate Shabbat, on folio 87, Rabbi Akiva is quoted saying that the word above refers to the limitations imposed on the people, their being warned not to approach the mountain too closely as well as Rabbi Yoseph son of Rabbi Yehudah, according to whom G–d told the people first about the reward in store for people observing the Torah. Different scholars argue about whether Moses told the people first about the punishment for not observing the Torah, or whether he told them first about the reward in store for the people if they observed the laws of the Torah. The Ten Commandments were given on the Sabbath, as Rabbi Akiva said, the verse supporting being Isaiah 30,15: בשובה ונחת תושעון, “your salvation will come about by quiet and stillness.” The first time we hear about the concept as of stillness and quiet is when G–d rested on the seventh day of Creation. The second set of Tablets was also given to the people on a Sabbath, i.e. the Day of Atonement, also known as שבת שבתון, the “ultimate” Sabbath.