The second difference: When a person relies on G‑d, his soul and heart are at ease with respect to all of G‑d’s decrees due to his knowledge that the Creator directs them for his good, both in this world and in the World to Come.

וְהַשֵּׁנִי, כִּי הַבּוֹטֵחַ בֵּאלֹהִים נַפְשׁוֹ בִּמְנוּחָה וְלִבּוֹ שָׁלֵו מִצַּד הַגְּזֵרוֹת, לְדַעְתּוֹ כִּי הַבּוֹרֵא יַנְהִיגֵן לְטוֹבָתוֹ בְּעוֹלָמוֹ וְאַחֲרִיתוֹ,

A person who knows that everything that G‑d does is for the good can feel at peace, knowing that he is in good hands.
The author now quotes a verse from Psalms as proof:

As King David of blessed memory said (Psalms 62:6 ): Only to G‑d should you hope, my soul, for my hope is from Him.

כְּמוֹ שֶׁאָמַר דָּוִד עָלָיו הַשָּׁלוֹם (תהלים סב ו) "אַךְ לֵאלֹהִים דּוֹמִּי נַפְשִׁי כִּי מִמֶּנּוּ תִּקְוָתִי."

Conversely, a person who does not rely on G‑d is in a state of constant grief and protracted anxiety. Mourning and sadness will not depart from him, both when things are going well for him and when they are not.

וַאֲשֶׁר אֵינֶנּוּ בּוֹטֵחַ בֵּאלֹהִים הוּא בְּצַעַר תָּדִיר וּדְאָגָה אֲרֻכָּה וְאֵבֶל וְעֶצֶב, לֹא יָמוּשׁוּ מִמֶּנּוּ בְּטוֹבָה וּבְרָעָה:

Even when things go well for him, he is not happy or calm:

When things go well for him, he is sad and anxious because of his lack of satisfaction from his current state of being and because of his aspirations to add, increase, and amass wealth.

בְּטוֹבָה מִפְּנֵי מִעוּט רְצוֹתוֹ בְּמַצָּבוֹ, וּשְׁאִיפָתוֹ לְהוֹסִיף וּלְהַרְבּוֹת וְלִכְנוֹס;

When things go badly for him, he is sad and anxious because he loathes that situation, which goes against his desires, nature, and character traits. As the wise man, King Solomon, said (Proverbs 15:15): All the days of a poor man are bad, but he who has a cheerful heart always has a feast.

וּבְרָעָה מִפְּנֵי שֶׁהוּא קָץ בָּהּ וְהִיא כְּנֶגֶד תַּאֲוָתוֹ וְטִבְעוֹ וּמִדּוֹתָיו. וְכֵן אָמַר הֶחָכָם (משלי טו, טו) "כָּל יְמֵי עָנִי רָעִים, וְטוֹב לֵב מִשְׁתֶּה תָמִיד."

The poor man in the verse refers to a person who lacks bitachon and is of poor intellect, because he doesn’t realize that everything is from G‑d and is for his good.