Or HaChaim on Numbers 20:13/אור החיים על במדבר כ׳:י״ג

1 המה מי מריבה, they are the waters of strife, etc. Why did the Torah mention "strife" twice in this verse, first מי מריבה, and then אשר רבו בני ישראל? The first word מריבה could easily have been skipped. Furthermore, from the words אשר רבו בני ישראל את השם I gain the impression that the subject in the words are the children of Israel, whereas from the words ויקדש בם it appears that the subject of the verse are Moses and Aaron?

2It appears that our verse wanted to explain why in this instance G'd had been so adamant about the sanctification of His name. The Torah writes המה מי מריבה to tell us that the strife justifies G'd's being adamant. By repeating the words אשר רבו the Torah wished to tell us that in this instance the Israelites were justified to quarrel with G'd (as they were entitled to water). The words ויקדש בם mean that G'd responded by taking action in order that His name should be sanctified amongst them, i.e. through the Israelites. G'd did this by instructing Moses to speak to the rock which the Israelites suggested because if that rock would produce water His name would be greatly enhanced seeing that He had demonstrated complete control even in the desert, and that the desert did not need to be an area spawning nothing but death as the people had thought so far. Now that Moses and Aaron had prevented G'd from demonstrating all this, G'd had become very angry that the opportunity had been missed to sanctify His name. Other sages interpret the words ויקדש בם as a reference to Moses and Aaron. G'd's name was sanctified through the punishment of Moses and Aaron as G'd demonstrated that He does not allow even those closest to Him to ignore His instructions without being punished.