We are in Pesukeh Bitachon, now in Divreh Hayamim 2, chapter 13. We are going to focus on pasuk 18, but first we need some background:
The dynasty of David was split into two camps- one was Yehuda, the Davidian Dynasty of Shlomo’s son, Rechavam, and the other camp, Yisrael, was under a king was called Yeravam.
This story took place in a later era when the king over Yehuda was Aviyah and the king over the rest of the Jewish people was Yeravam. They were going to war against each other. Aviyah had 400,000 men and Yeravam had 800,000 men that are referred to as Gibor Hayil/great warrior. So it seems that Yeravam had more power than Aviyah in this fight, as he has double the amount of troops.
Then Aviyah gets up to make a speech, telling them that they had veered from the kingdom of David. He referred to Yeravam as a slave and said the people that joined him were all empty people. He used a very negative term, Beliya’al/ lawless people, and then proceeded with more negativity toward the other side. The Hachamim were not happy with him because he should not have should spoke negatively about all the Jewish people.
The Yerushalmi, in Yevamot 16,3 says that ultimately he was punished with death in this war, because he called all of Yeravam’s people worthless and lawless people. But as we will soon see, although he gets killed in the war, his side wins, which is important for our story.
They had a very fierce hand to hand battle, and it looked like Aviyah would lose, but his people called out to God and started blowing on their trumpets, which is what you're supposed to do when you're in war, to strengthen yourself, your belief, your faith and teshuva.
And at that point, they started winning the battle, and the people of the other camp, Yisrael, started running away.
In the end, Aviyah killed 500,000 out of the 800,000 soldiers. So 400,000 killed 500,000, which was a seemingly miraculous victory.
And then it says (and this is our pasuk)
וַיִּכָּנְעוּ בְנֵי יִשְׂרָאֵל בָּעֵת הַהִיא וַיֶּאֶמְצוּ בְּנֵי יְהוּדָה
The children of Israel (meaning the team that Yehuda was fighting) became humbled at that time, and the people of Yehuda gained Ometz/ strength
Why ?
כִּי נִשְׁעֲנוּ עַל ה' אֱלֹהֵיאֲבוֹתֵיהֶם
Because they relied on Hashem, the God of their fathers.
This pasuk is here to tell us the secret of their victory.
But there's more background to it: The famous Ramchal , Rav Moshe Chaim Luzzatto, author of Mesilat Yesharim, had a student, Rav David Vali, author of Ner Yisrael, a commentary on the Neviim and Ketuvim.
In that Sefer he says like this, he says
מן הדין היה צריך השי׳ת לעזוב את אביה
God really should have forsook Aviyah,
Because the of the negative things he said in his speech, but he relied on Hashem, and therefore for the respect of God, God fought for him and had him win against the enemies this time.
Although he would be punished for the sins that he did, because he had bitachon, he would win. Why?
כי מן הדין שיתגברו שמרי תורה על עוזבי תורה
The law dictates that those that guard the Torah should overtake those that forsake the Torah.
Aviyah’s team were considered the guardians of Torah because when they saw that they were going lose with the natural way, they relied on Hashem and He saved them.
He said it became apparent, the difference between the Mushkachim/those were supervised by God, and those people that forsake the holiness..
Because those that are supervised are going win, and those that are clinging to the negativity will lose.
As we say,
הֵ֭מָּה כָּרְע֣וּ וְנָפָ֑לוּ וַאֲנַ֥חְנוּ קַּ֝֗מְנוּ וַנִּתְעוֹדָֽד
They fall and they are humble, and we stand strong.
The lesson is that even though a person might have sinned, if he announces his bitachon, respect of God says that he should be successful.
Although he'll be punished for whatever he did, right now he relied on Hashem and Hashem is going come through for him.
Have a wonderful day.