Parents have an obligation to their children. We are to invest in them, to guide them and teach them. And when everything goes south anyway, we are still obligated to follow a process:
If a man have a stubborn and rebellious son, who will not obey the voice of his father, or the voice of his mother, and that, when they have chastened him, will not hearken to them: then shall his father and his mother lay hold of him, and bring him out to the elders of his city, and to the gate of his place; and they shall say to the elders of his city, This our son is stubborn and rebellious, he will not obey our voice; he is a glutton, and a drunkard. (Deut. 21)
In the event that a son is rebellious, there is a process:
1: The parents must speak to the son, chastising him; and
2: Then the son must ignore their words. After which,
3: The parents can condemn the son and label him a “rebel.”
Parents may not jump out of sequence: the son must get a chance to change his mind before he is condemned.
What if the Torah gives us an example of this happening to someone?
Moses and Aharon function, in a way, as the father and mother of the people. Moses leads and sets the moral tone, but Aharon creates and maintains the home (for both man and G-d) and seeks to find compromises at every opportunity.
Here is where Moses and Aharon are judged as parents:
And there was no water for the congregation: and they gathered themselves together against Moshe and against Aharon. And the people quarrelled with Moshe, and spoke, saying, “Would that we had died when our brethren died before the Lord! And why have you brought up the congregation of the Lord into this wilderness, that we and our cattle should die there? And why have you made us come up out of Miżrayim, to bring us in unto this evil place? it is no place of seed, or of figs, or of vines, or of pomegranates; nor is there any water to drink.” And Moshe and Aharon went from the presence of the assembly to the door of the Tent of Meeting, and they fell upon their faces: and the glory of the Lord appeared to them. And the Lord spoke to Moshe, saying, “Take the rod, and gather the assembly together, thou, and Aharon thy brother, and speak to the rock before their eyes; and it shall give forth its water, and thou shalt bring forth to them water out of the rock: so thou shalt give the congregation and their beasts drink.” And Moshe took the rod from before the Lord, as he commanded him. And Moshe and Aharon gathered the congregation together before the rock, and he said to them, “Hear now, you rebels; shall we fetch you water out of this rock?” And Moshe lifted up his hand, and with his rod he smote the rock twice: and the water came out abundantly, and the congregation drank, and their beasts also. And the Lord spoke to Moshe and Aharon, “Because you did not believe in me, to sanctify me in the eyes of the children of Yisra᾽el, therefore you shall not bring this congregation in to the land which I have given them.”
Moses and Aharon ignored the process. They did not talk to the complaining people at all – they went to talk to G-d instead. Moses does not chastise the people so that they have an opportunity to change themselves. Instead he (without Aharon, his “co-parent”) calls them “rebels”, without giving them a chance to correct their ways.
What if Moses’ refusal to follow the process of handling a rebellious son is the reason Moses was not allowed to go into the Land? Moses is not just a parent – he is also the exemplar of Jewish Law. Wouldn’t ignoring legal process disqualify one from ongoing leadership?
Beyond this: what if Moses’ refusal to be follow G-d’s instructions is, in a small way, Moses acting as a rebellious son? After all, G-d tells Moses what to do, and Moses does not listen. So while Moses labels the people “rebels,” it is Moses himself who acted in that way?!
Moses gives up on the people, and he does so prematurely, just like a parent who loses his temper before giving his son a chance to straighten out. Our power as parents is not unlimited, and we must follow due process.
P.S. The neat thing about this answer is that it really incorporates the rest of the answers that the text suggests (i.e. Moses hit the rock instead of speaking to it; He hit the rock twice; Moses’ initial reaction, which was to run away to talk to G-d, instead of confronting the people initially, showed a lack of faith; Moses also may have used the wrong staff (when Moses extracted water from a rock at Massah, he used Aharon’s staff); Lastly, Moses condemned the people as “rebels,” losing both his temper and his ability to lead by example – remember that the first named sin in the Torah is Cain giving into his temper). All are connected to this idea of respecting the instructions and process, instead of giving in to momentary anger.