John Calvin's Bible Commentary
Numbers 17:1
1.And the Lord spoke unto Moses. Howsoever stubborn the Israelites might be, yet their hardness of heart being now subdued, and their pride broken down, they ought to have acknowledged the authority of the priesthood, and to have perpetually held it in pious reverence. But it is plain from the confirmation of it, which is now added, that they were not yet thoroughly overcome. For God never appoints anything in vain; the remedy, therefore, was necessary, that He now applied to that disease of obstinacy which He perceived still to maintain its secret hold upon their hearts. Herein we also behold His inestimable goodness, when He not only had regard to the relief of their infirmity, but even struggled with their depravity and perverseness, in order to restore them to their senses. In the same way also He now deals with us, for he not only strengthens the weakness of our faith by many aids, but He puts constraint upon our light and inconstant minds, and retains us in the path of duty though we strive against Him. He likewise anticipates our willfulness, so as to keep us from growing presumptuous, or rouses us up when we are disposed to be slothful. In fact, his our business so to apply to our use whatever helps to faith and piety He sets before us, as to be assured that they are so many pieces of evidence to convict us of unbelief Although, therefore, the majesty of the priesthood had been already sufficiently, and more than sufficiently established, still God saw float in the extreme perversity of the people there would be no end to their murmurs and rebellions, unless the final ratification were added, and that, too, in a season of repose, inasmuch as, whilst the sedition was in progress, they were not so disposed and ready to learn. By this confirmation, then, He set aside whatever doubts could at any time arise, when Aaron’s rod, severed as it was from the tree, was the only one of the twelve which blossomed. For it was no natural circumstance that a branch which derived no sap from the root, and which at that season of the year would have been dry upon the tree, should produce flowers and fruit, when it was east before the Ark of the Covenant, whilst the others, although altogether similar, remained dry and dead.