Radak: The water came to them via sin and complaining.

Malbim: They sinned more; they doubted His ability. This is because they were sunk in corrupt mindsets that they 'inherited' in Egypt, that Kel Elyon, the Cause of causes, does not oversee individuals; he apportioned Divine power to individual natural forces. This one rules over water, this one over food

Rashi: It is to anger, like "Mamrim Heyisem" (Devarim 9:7).

Radak: This is like Lehamros. Similarly, "Latzbos Beten" (Bamidbar 5:22, is like Lehatzbos). It says also "Lamros Enei Chevodi"; this is rebellion.

Radak: He is above everything, and all is in His hand. Malbim - their rebellion was against Kel Elyon, the Cause of causes; they denied that He supervises in the Midbar.

Radak: It is in the Midbar.