Deuteronomy 5:23

23.And it came to pass, when ye heard. Lest the Israelites should undervalue his teaching, because he had been put between them by God as their minister, Moses meets the objection, (by reminding them) that it was done at their petition and request. We know how proudly they were wont to reject him; as if they saw in him nothing but what was earthly and human; it was needful, then, that God Himself should speak to rescue His servant from the contempt of posterity. For the people themselves, being convicted of their foolish and preposterous request, could never afterwards have any pretext for rejecting Moses, as if he had not evidenced the truth of his calling. And here their astonishing perverseness betrayed itself, in not being ashamed to refuse credit to the holy Prophet, after he had been approved by so many miracles. Assuredly, if they had been just and honest judges, it would have been sufficiently notorious, and certain to them, that Moses did not speak of himself, or of his own impulse, but that he was the organ of the Spirit; yet the doctrine of God was scorned by these proud, and perverse, and fretful beings, because it was brought to them by the hands of a mortal man. They, therefore, by their importunate desires, draw down God from heaven, to speak Himself; but immediately terror seizes on their minds, so that they flee from His voice. Thus experience taught them that there was nothing better for them than to hear God speaking to them by the mouth of Moses; and they were instructed by the just reward of their temerity to choose and prefer that mode of teaching which they had spurned; for, if in future they refused to give credit to Moses, whom they had themselves chosen as their mediator with God, they brought themselves in guilty of gross and wicked contumacy; and this is what he now reproaches them with. It would have been worse than unseemly in them, when God had yielded to their prayers, to reject that blessing which they had besought of Him. On this account he reminds them, that, after they had been eye-witnesses of God’s fearful power, they had voluntarily asked that He should not speak to them any more; and, lest they should object that this was done only by a few, or inconsiderately, or in tumult, he expressly testifies that these requests were presented by the heads of their tribes, and their elders.