Numbers 20:12 - Wesley's Explanatory Notes

Ye believed me not — But shewed your infidelity: which they did, either by smiting the rock, and that twice, which is emphatically noted, as if he doubted whether once smiting would have done it, whereas he was 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 implies 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 farther 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 peoples perverseness. In the eyes of Israel — This made their sin scandalous to the Israelites, who of themselves were too prone to infidelity; to prevent the contagion, God leaves a monument of his displeasure upon them, and inflicts a punishment as publick as their sin.