King Shaul's Great Mistake
King Asa's real mistake was not making teshuvah after he flubbed up everything else.
Part of his denial included getting angry at the messenger and persecuting people who were not only innocent, but right.
King Shaul made the same error.
First of all, King Shaul committed a terrible blunder by not destroying ALL of Amalek.
(He left King Agag alive long enough for this Amalekite king to conceive a child, which perpetrated the Amalek line.)
With sources pinpointing Amalek as Germany, we start to fathom the depth of this failure to completely destroy Amalek.
While most focus on Amalek deals with the Nazis, one of the most devious facets of Amalek lies in its ability to chill a person's enthusiasm for Torah & mitzvot.
Decades before Hitler yemach shemo came into the world, the Haskalah & Reform movements developed within German Jewry—classic examples of chilling enthusiasm for Torah & mitzvot.
Also, think of the prime nemesis in Megillat Esther: Haman the Agagi—a direct descendant of Amalek via King Agag.
None of these terrible people would've existed had King Shaul fulfilled Hashem's command in its entirety.
In fact, based on the above, one wonders whether the Haskalah & Reform movements would've developed without a German culture rooted in Amalek.
Food for thought...
Anyway, while King Shaul managed to admit his terrible blunder, he struggled to against the personal outcome: the loss of the royal line for his descendants.
What Could Have Been
Had he accepted God's decree, he could have completed his reign, to be succeeded by his faithful son-in-law, David.
The Me'am Lo'ez further notes:
By rejecting God's decree, he brought unnecessary sorrow upon himself, his family, and the Jewish people.
He could have completed his reign. As the powerful king, King Shaul could have done wonderful things for Am Yisrael.
Instead, he reigned for only 2 years, then died a tragic death.
Just like King Asa later, King Shaul could not move forward.
His despair & shame warped into anger at others, which he expelled onto innocent people.
A Modern Tale of Making Things Worse for Oneself
What happened?
At an Israeli beach, his brother spied a young damsel and went to talk to her.
Little did they know she was the daughter of a big mafia guy.
Her bodyguards stopped the guy, who objected.
Not sure when the fighting turned physical, but at some point, the other brother (the successful businessman) jumped into the fray (before or just as it became physical), and this called for revenge as far as the mafia bigwig was concerned.
One night, the brother was out driving when another car showed up behind him and proceeded to tail him.
No matter which way he turned, the car followed him.
He understood it was the mafia, so he refused to go home for fear of endangering his family.
As the hours went by, his fear increased and his fuel tank decreased.
Finally, panicked & exhausted, his car crashed into a wall, killing him.
(He contacted his successful business brother during the drive, which is how the successful brother knew what happened.)
Despite the certainty of this being a passive-aggressive mafia hit, lack of proof made any action impossible.
Plagued by guilt, the successful business man see-sawed between depression & rage, and also started to drink.
His reckless emotional state affected his business, and he lost that too.
At one point, he ended up in jail temporarily.
While his decision to alongside his brother (rather than calming his brother and pulling him away from the scene) was clearly a foolish & dangerous decision, why did his family need to suffer?
Why did he need to turn to alcohol and lose his entire livelihood?
Things were bad—true.
But things did not need to get SO bad—that's also true.
His brother's life was already destroyed—that parsha is over.
But for a while, he needlessly destroyed his own life (and that of his wife & children) in response.
Why go to a mixed beach? (Yes, I realize they aren't frum. Guess what? Halacha applies to everyone whether they know it or not. Spiritual physics continue whether you believe in them or not.)
And once at a mixed beach, why start up with a damsel?
And if the damsel's bodyguards get in the way, why fight them?
That's pretty animalistic, if you think about it.
A couple of guys tell you to leave the damsel alone and you fight for them for the right to your taavah?
Isn't that what rutting baboons & elephants in musth do?
Not exactly one of Tzelem Elokim's nobler moments.
What are the Messages for Us?
He got back on his feet again, proving that Hashem not only gives second chances, but third, fourth, and fifth chances too.
Intriguingly, both King Shaul & King Asa seemed born for greatness.
Via inborn nature & upbringing & lineage, both possessed the sterling external & internal qualities to make the ideal king.
And both got off to blazing start.
And while both are remembered for the good they did, neither ended on the note which they started.
In contrast, David Hamelech had nearly ever strike against him—and look who became the eternal royal line for Mashiach.
Look who produced the everlasting Book of Tehillim.
David Hamelech also blundered.
He encountered his failures.
But he never despaired.
Did he eat himself up, beat himself up, or drown in the kind of toxic shame that leads to the abuse of others?
No.
He always picked himself back up again & kept moving forward.
As the Me'am Lo'ez states on page 365:
Though by his earlier mistakes, a person may have lost a truly great potential, there is much left for him.
God still loves him and has not abandoned him.
If he trusts God and remains faithful, he can yet enjoy great blessing.
https://www.aish.com/jl/h/cc/48936347.html
The long version (start with this link, then keep follow the links at the bottom right):
https://www.chabad.org/library/article_cdo/aid/463971/jewish/Saul-First-King-of-Israel.htm