John Calvin Commentary Exodus 19:8

"And all the people answered together, and said, All that Jehovah hath spoken we will do. And Moses reported the words of the people unto Jehovah." — Exodus 19:8 (ASV)

And all the people answered. We will see in its proper place why God employed Moses as a messenger to carry the commands and replies back and forth. For now, Moses merely relates what all the people answered, namely, that they would be obedient in all things. It was not a part, but the whole of the people who promised this, and their reply was unreserved, declaring that they would do whatever God required.

Yet soon after, they relapsed into their natural way of thinking and did not keep their promise even in the smallest degree. Still, we may believe that they spoke without deception. Although they had no intention of deceiving God, they were carried away by a kind of impulsive zeal and deceived themselves.

Nor was it Moses’s objective to tell them in reproach that they had lied to God, or deceitfully boasted with their lips what they did not feel in their hearts. Instead, by stating how ready they were to obey, he removes from them any future claim of ignorance.

Nor is there any doubt that God inclined their minds to this receptiveness in order to establish the doctrine of His law.

Meanwhile, let us learn from their example that we must not merely obey God’s word out of some sincere impulse. A rash feeling is of no use unless it is followed by constant perseverance. Therefore, let us learn to examine ourselves well, lest we rashly promise, without serious self-examination, more than we are able to perform.

Yet we must not forget what I have already said: they were all made willing by the secret inspiration of God, in order that they might be witnesses to themselves and others of the many signs by which the truth and faithfulness of the²¹² heavenly doctrine was then confirmed.

²¹² La Loy. — Fr..