Leviticus 10:16

16.And Moses diligently sought the goat of the sin-offering Moses had not omitted to tell them what was to be done with the goat; and the sacrifice which he had himself performed, was a visible instruction to them. He had set before them what they should imitate, and this would have been enough even for children. But, as I have said, in such serious matters Moses had not spared labor and care, whereas the sons of Aaron, as if they had neither heard nor seen anything of the sort, pervert the whole order of them, although they had been just before reminded that they had been appointed to keep the charge of God. Perhaps they were impelled to this error by the trouble arising from their grief; but we gather from hence that however exquisite may be the ability of masters and teachers, it may be often fruitless unless they have obedient scholars with retentive memories. And hence also we learn that when God often inculcates the same thing, His labor is not superfluous, because we do not understand what we seem to understand; or what has been clearly shewn to us soon afterwards escapes.

Further from the anger of Moses, which is mentioned in his praise, we may infer that the transgression was no light one, although it was not so severely punished as the presumption of Nadab and Abihu. The excuse which some make for them, or allege in extenuation of their crime, that they thought they were deprived of the right before accorded to them, and therefore abstained through modesty, is refuted by the answer of Aaron himself. It was, therefore, grief alone which impelled them to this error. But the reason why God was more merciful to them than to their brethren, is only known to Himself. Conjectures may, indeed, be advanced; but at last we must come to this, that because God’s judgments are hidden, they are not therefore unjust; but that we must humbly adore their depth into which the minds of men cannot penetrate.

19.And Aaron said unto Moses, Behold, this day Aaron replies that it arose from pious fear that they had not feasted before God, because they would in a manner have defiled the sanctuary by their tears and melancholy, as if he had said, Part indeed of the sin-offering was reserved for our food, but we could not properly partake of it except in cheerfulness and with thanksgiving. The grief arising from his sudden bereavement did not allow of this; but it was not a just defense; for he ought rather to have striven against the feelings of the flesh, so that his domestic calamity should not withhold him from the service of God. But, inasmuch as in his perplexity his fear was deserving of pity, Moses forgives him; and it is said that he was appeased, because he finds less of evil than he supposed.