Until now the author has been explaining in general terms that when a person relies on anything other than G‑d he is doomed to fail. Now the author brings specific examples of things that people tend to place their trust in, and how they do not provide security:

If he relies on his wisdom, his schemes, his physical strength, and his own efforts, those efforts will be for naught; he will become weak and lose that physical strength, and his schemes and wisdom will fall short of accomplishing his goals, as the verse says (Job 5:13): He traps clever people in their shrewdness.

וְאִם יִבְטַח עַל חָכְמָתוֹ וְתַחְבּוּלוֹתָיו וְכֹחַ גּוּפוֹ וְהִשְׁתַּדְּלוּתוֹ, יִיגַע לָרִיק וְיֶחֱלַשׁ כֹּחוֹ וְתִקְצַר תַּחְבּוּלָתוֹ מֵהַשִּׂיג חֶפְצוֹ, כְּמוֹ שֶׁאָמַר הַכָּתוּב (איוב ה, יג) "לוֹכֵד חֲכָמִים בְּעָרְמָם."

This verse is cited as proof that man cannot rely on his plans, however shrewd they may be.

Relies on his wisdom. On the verse, If you eat the toil of your hand (Psalms 128:2), the Alter Rebbe, Rabbi Shneur Zalman of Liadi, explains: The verse does not say “the toil of your head,” because we must work for a livelihood solely with physical abilities—the hands. The internal faculty of the mind (“head”), on the other hand, is to be utilized for the study of Torah (Likkutei Torah, Shelach 42d).

If he relies on his wisdom… his physical strength, and his own efforts. Although we must not rely on our wisdom and efforts to achieve our goals or earn a living, we can and should utilize our strengths and abilities, because they are the vehicle that G‑d gave to achieve success. We must simply be aware that blessings and success ultimately come from G‑d, and that it is G‑d Who ordains blessings through the channel of human effort.

The Sages explain that we are biblically mandated to work: Expounding on the verse, And G‑d will bless you in all that you do (Deuteronomy 15:18), Sifri states, “The person might think that he can sit idle (and do nothing); therefore, the verse teaches us ‘in all that you do ’” ( Likkutei Sichot, vol. 31, p. 172 ff. ).

In fact, in Chapter 4 (of the Gate of Trust), the author writes: “With the clear conviction that his affairs are given over to the decrees of the Creator, may He be exalted…. he must at the same time pursue means beneficial to him and choose what appears to him to be the best [course of action] in the matter.”

Bottom line
Utilize your abilities and strengths because it is your G‑d-given vehicle for success.

And as it says (Ecclesiastes 9:11): I returned and saw under the sun that the race does not belong to the swift, nor the war to the mighty, and the wise do not have bread…

וְאָמַר (קהלת ט, יא) "שַׁבְתִּי וְרָאֹה תַחַת הַשֶּׁמֶשׁ, כִּי לֹא לַקַּלִּים הַמֵּרוֹץ, וְלֹא לַגִּבּוֹרִים הַמִּלְחָמָה, וְלֹא לַחֲכָמִים לֶחֶם."

It would be expected that those who are physically strong would win the war. This verse shows that physical strength and intelligence cannot be relied on for success.

And as it says (Psalms 34:11): Young lions suffer want and are hungry, but those who seek the L-rd do not lack any good.

וְאָמַר (תהלים לד, יא) "כְּפִירִים רָשׁוּ וְרָעֵבוּ וְדוֹרְשֵׁי ה' לֹא יַחְסְרוּ כָל טוֹב."

The “young lions” in the verse refer to strong people who rely on their strength. The verse teaches that they are destined to be poor and hungry. On the other hand, those who seek G‑d —meaning, those who rely on G‑d—will not lack any goodness.
From the above verses we see that a person cannot rely on his own talents for his success—only a person who relies on G‑d is guaranteed to be taken care of.
Having discussed how a person who relies on his own talents will not be successful, the author now turns to address a person who relies on his wealth:

And if he relies on his abundance of wealth, it will be removed from him and left to someone else.

וְאִם יִבְטַח בְּרֹב עָשְׁרוֹ: יוּסַר מִמֶּנּוּ וְיִשָּׁאֵר לְזוּלָתוֹ,

The author now quotes verses that illustrate the transitory nature of wealth:

As the verse says (Job 27:19): A rich man lies down with his wealth intact, he opens his eyes and it is no longer his. Similarly, the verse says (Proverbs 23:4): Do not toil to become wealthy, from your own understanding desist . And the next verse (ibid. 5) says: Before you can set your eyes on it, it is gone. Similarly, it says (Jeremiah 17:11): At a young age, his wealth will leave him, and at his end he will be a disgrace.

כְּמוֹ שֶׁאָמַר הַכָּתוּב (איוב כז, יט) "עָשִׁיר יִשְׁכַּב וְלֹא יֵאָסֵף, עֵינָיו פָּקַח וְאֵינֶנּוּ," וְאָמַר (משלי כג, ד) "אַל תִּיגַע לְהַעֲשִׁיר, מִבִּינָתְךָ חֲדָל," וְאָמַר (שם ה) "הֲתָעִיף עֵינֶיךָ בּוֹ וְאֵינֶנּוּ," וְאָמַר (ירמיה יז, יא) "בַּחֲצִי יָמָיו יַעַזְבֶנּוּ וּבְאַחֲרִיתוֹ יִהְיֶה נָבָל."

At a young age, it will leave him, etc. While this verse refers to a person who obtains his wealth dishonestly, the author quotes it as yet another source for the transitory nature of wealth.

Alternatively, even if the riches themselves are not removed from him, his ability to enjoy the wealth will be withheld from him by G‑d. As the wise man, King Solomon, said (Ecclesiastes 6:2): G‑d gives him no power to eat of it.

אוֹ תִּמָּנַע מִמֶּנּוּ הֲנָאָתוֹ בּוֹ, כַּאֲשֶׁר אָמַר הֶחָכָם (קהלת ו, ב) "וְלֹא יַשְׁלִיטֶנּוּ הָאֱלֹהִים לֶאֱכוֹל מִמֶּנּוּ."

If G‑d doesn’t want him to derive any enjoyment from his riches, why, then, does G‑d leave it in his possession?

It will be with him as a deposit, so that he will guard it from harm, until the time that it will be returned to the one who is deserving of it, and for whom it was meant.

וְיִהְיֶה אֶצְלוֹ פִּקָּדוֹן שֶׁשּׁוֹמֵר אוֹתוֹ מִן הַפְּגָעִים עַד שֶׁיָּשׁוּב לְמִי שֶׁהוּא רָאוּי לוֹ,

This concept—that sometimes a person is given wealth solely for the purpose of safeguarding it for another—is supported by two verses:

As it says (Ecclesiastes 2:26): And to the sinner, G‑d gives the urge to gather and amass wealth, to give to one who is good before G‑d. As it says (Job 27:17): The wicked man will prepare, and the righteous man will use it, and the innocent will divide the money among themselves.

כְּמוֹ שֶׁכָּתוּב (שם ב, כו) "וְלַחוֹטֵא נָתַן עִנְיָן לֶאֱסוֹף וְלִכְנוֹס לָתֵת לְטוֹב לִפְנֵי הָאֱלֹהִים," וְאָמַר (איוב כז, יז) "יָכִין וְצַדִּיק יִלְבָּשׁ וְכֶסֶף נָקִי יַחֲלוֹק."

The verse speaks about the wicked merely “preparing” for the righteous, implying that the wicked person does not derive any benefit from his wealth.
We discussed two possibilities of what might happen to a person who relies solely on his wealth: 1) He might lose it; 2) even if he retains it, he will not be able to enjoy it. Now the author goes further and says that sometimes not only is he not able to enjoy his wealth, but the wealth itself causes bad things to befall him:

It is possible that his money will be the cause of his misfortune, as well as the cause of the destruction of his soul.

וְאֶפְשָׁר שֶׁיִּהְיֶה הַמָּמוֹן סִבַּת רָעָתוֹ וְאָבְדַן נַפְשׁוֹ,

Sometimes money can be the source of a person’s physical and spiritual downfall.

The cause of his misfortune. Wealth is often a reason for arrogance and a feeling of superiority, which leads to sinful acts and betrayal of G‑d. As it states: And He will add to your silver and gold, then your heart will become arrogant and you will forget the L-rd, your G‑d (Deuteronomy 8:13-14; Pat Lechem ).

Bottom line
Understand your wealth and don’t let it become an impediment.

As the verse says (Ecclesiastes 5:12): There is a sickening evil that I have seen under the sun—riches hoarded by their owner, to his own misfortune.

כְּמוֹ שֶׁכָּתוּב (קהלת ה, יב) "יֵשׁ רָעָה חוֹלָה רָאִיתִי תַּחַת הַשָּׁמֶשׁ, עֹשֶׁר שָׁמוּר לִבְעָלָיו לְרָעָתוֹ."

Until now, the author elaborated on the first spiritual advantage of bitachon, namely that it causes the person to feel at ease. A person who relies on other people or his own talents or wealth will always worry that his success will not last.