What does « Heavy rain / Punishment » mean in the Quran?

O you who have believed, do not invalidate your charities with reminders or injury as does one who spends his wealth [only] to be seen by the people and does not believe in Allah and the Last Day. His example is like that of a [large] smooth stone upon which is dust and is hit by a downpour that leaves it bare. They are unable [to keep] anything of what they have earned. And Allah does not guide the disbelieving people.

And the example of those who spend their wealth seeking means to the approval of Allah and assuring [reward for] themselves is like a garden on high ground which is hit by a downpour - so it yields its fruits in double. And [even] if it is not hit by a downpour, then a drizzle [is sufficient]. And Allah, of what you do, is Seeing.

O you who have believed, do not kill game while you are in the state of ihram. And whoever of you kills it intentionally - the penalty is an equivalent from sacrificial animals to what he killed, as judged by two just men among you as an offering [to Allah] delivered to the Ka'bah, or an expiation: the feeding of needy people or the equivalent of that in fasting, that he may taste the consequence of his deed. Allah has pardoned what is past; but whoever returns [to violation], then Allah will take retribution from him. And Allah is Exalted in Might and Owner of Retribution.

[Theirs is] like the example of those shortly before them: they tasted the bad consequence of their affair, and they will have a painful punishment.

Has there not come to you the news of those who disbelieved before? So they tasted the bad consequence of their affair, and they will have a painful punishment.