"Back in Exodus 17:1-7, we had a similar incident. There God said to Moses: 'Go out, strike the rock with a rod, water will come out.' Here He says, 'Go out and speak to the rock and water will come out.' Moses goes out, gives a brief speech in verse ten [Num. 20:10] ... 'struck the rock twice, and water came forth abundantly ...'
"Note that 'water came forth abundantly' ... That's the first thing you ought to note here -- he [Moses] was a success. The people are thirsty. He strikes the rock and water comes forth in super-abundance, and their needs are met. If you're going to look at this, humanly speaking, you'd have to say it got the job done. No, it's Moses' greatest failure!
"I'm somewhat puzzled by that. I think he might have struck the rock and nothing would have happened. But he struck the rock and water came out. Were the whole nation of Israel to evaluate that you would have to say, 'There's another evidence that Moses is the servant of God.' But you know what this is? It's an evidence of rebellion in Moses' heart.
"I need to be very careful. Sometimes we as believers are duped into looking at what we call 'results,' and saying, 'God must be blessing that ministry. Look at what is happening! People get saved! Needs are met! How can you criticize that?' [But] keep in mind that this is Moses' greatest failure! For this sin, he will not go into the land of Canaan! All that he has done, all of his faithfulness, all of his intercession ... And here water is provided abundantly, and for this sin, Moses is not going into Canaan.
"I need to be very careful. It's not just the results that God's looking at. He wants it done His Way. The issue is not whether people get saved or not. The issue is: Is it done God's way?! He can save anybody He wants, anytime. What He has called us to do is do it His way. ... I look and say, 'Well, things are happening. That's God's mark of approval.' It is if it's happening God's way. It may look great to everybody else -- 'What can you say? Water -- abundantly -- the congregation and all their animals drank. What more could you ask for?' OBEDIENCE! Moses failed [Num. 20:12]!
"God says to Moses: 'The problem here, and the reason you can't go in, is your unbelief -- you rebelled against Me' [Num. 20:24; Psa. 106:32,33]. And the result is [that God] was not held up as holy before the people. You see what happens when I rebel against God, when I don't do it His way? -- God is not exalted as holy before the people. 'They got their water didn't they? It was supernatural! What difference did it make to Israel, whether Moses struck the rock or spoke to the rock? Why would that affect God's holiness?' God's holiness is exalted only when I serve Him in obedience. [And only then can one's ministry be deemed a success.]"
* Taken from a commentary on Numbers 20:8-12, preached 10/11/87 (Gil Rugh).