Numbers 20:12 - Joseph Benson’s Commentary on the Old and New Testaments

Ye believed me not But showed your infidelity; which they did, either by smiting the rock, and that twice, which is emphatically noted, as if they doubted whether once smiting would have done it; whereas, they were not commanded to smite so much as once, but only to speak to it: or, by the doubtfulness of these words, (Numbers 20:10,) Must we fetch water out of the rock? which implied a suspicion of it; whereas they should have spoken positively and confidently to the rock to give forth water. And yet they did not doubt of the power of God, but of his will, whether he would gratify these rebels with this further miracle, after so many of the like kind. To sanctify me To give me the glory of my power in doing this miracle, and of my truth in punctually fulfilling my promise, and of my goodness in doing it, notwithstanding the people's perverseness. In the eyes of Israel This made their sin a cause of stumbling to the Israelites, who of themselves were too prone to infidelity; and, to prevent the contagion, God leaves a monument of his displeasure upon them, and inflicts a punishment as public as their sin.