21. And the Lord said unto Moses. By God's command the same prohibition is repeated, that the people should not pass over the bounds, because, without doubt, it was not enough to have forbidden them once, as we may gather from the reply of Moses; for he thought that since they were all admonished, there was no necessity for a new prohibition. But God insists with greater vehemence, and again with threatenings, orders them to be charged that they take diligent heed to themselves. He knew, forsooth, that He had to do with the rebellious, for whose subjugation a sorer dread of punishment would be necessary. Now, since we are no better than they, let us not be surprised if God often spurs us on by the application of many exhortations, and redoubles His threats, for else forgetfulness of all which He has once enjoined would creep over us. This passage also confirms the fact, that the curiosity which influences men's minds is greatly displeasing to God; for He expressly commands that they should not break through to gaze, -- not because He would have anything concealed or hidden which it was profitable for them to know, but because their inquiries ought to be sober; and this is the legitimate limit of knowledge, humbly to learn at God's mouth what He voluntarily teaches, -- not to advance with too anxious longings, but to follow Him as He leads us.

23. And Moses said unto the Lord. Because Moses was persuaded that the people would be obedient, he rejoins that the decree which had already been pronounced would be sufficient, and that the repetition of it would be in some degree supererogatory; for when he says that "the people cannot come up," he replies that he puts himself forward in the name of all as their surety. And this he does honestly, and in accordance with the rule of charity; yet it appears from God's reply that he was deceived, whilst judging of others by his own feelings. Whilst, however, he unhesitatingly executes the task allotted to him, it is plain that he preferred the command of God to his own preconceived opinion; and thus taught us by his example, that whatever may be the imaginations which come into our minds, they must still be submitted to this yoke, that God's authority alone may have the pre-eminence. A doubt may arise because He names "the priests;" since the priestly office was not yet committed to the Levites. Some, therefore, understand it to mean all the first-born, because, by ancient and common consent, it is allowed that they were always invested with the honor of the priesthood. But although I readily admit that they were chosen from the first-born, yet I do not think it probable that out of that immense multitude there were special priests for every house. In the meantime we may conjecture that since no heathen nations were then without priests, there was no less method amongst the chosen people; for what common sense dictated to the blind, assuredly a purer religion more clearly showed, viz., that God's worship should not be separated from the priesthood.