The Midrash writes in the beginning of Vayikra (Vayikra Rabbah 1:1):

"Bless Hashem O his angels; the strong warriors who do His bidding, to obey the voice of His word." (Tehillim 103:20) What is the verse writing about? It has already been written: "Bless Hashem, all His [heavenly] hosts." This must be talking of the lower realms.

R. Yitzchak says: The verse is speaking of shemita observers. It is normal for a person to do a mitzvah for one day, one week, and one month. Could it be for the rest of the year? Yet, this person (the owner) sees his field empty, abandons his vineyard and pays taxes and is silent – is there a stronger hero than this?!

We can see from this that the great virtue of shemita observers is not that they abandon their fields and vineyards. It is their silence that awards them with the title "strong warriors." What is this virtue of silence?

It says in our Parsha (Vayikra 25:20-21):

If you will say: "What will we eat in the seventh year? – behold! We will not sow and not gather in our crops!" I will ordain My blessing for you in the sixth year and it will yield a crop sufficient for the three year period.

Why does the Torah make the blessing dependant on the question: "If you will say: What will we eat in the seventh year?" Does this mean that if the question remains unasked, then Hashem will not bless the shemita observers?!

Chazal write: "[Hashem] looked in the Torah and created the world." The world was created based on the Torah: "In the beginning G-d created the heavens and the earth." (Bereishit 1:1) Hashem created the world for the Torah, which is called "beginning" and for Am Yisrael, who are also called a beginning, "the beginning of his crop." (Rashi)

Therefore, there is no mitzvah in the Torah that is impossible to fulfill. If the mitzvah of Shemita is written in the Torah, and there is a prohibition upon the person to sow and reap during that year –  then the world is built in such a way so that a person will naturally have food. The world was built so that a person can observe the mitzvah properly without any need for a special blessing guaranteeing him food and support during the Shemita.

Therefore, there is no real need for: "I will ordain My blessing," because Shemita exists naturally in creation and Hashem feeds and supports everything he creates. Therefore, anyone who fully believes and trusts in Hashem and knows that Hashem: "looked in the Torah and created the world" – has no need to question. He will stop working the land during the Shemita and trust Hashem to provide him with his needs.

However, there are people who somewhat lack trust in Hashem, and they ask: "What will we eat in the seventh year?" Them, Hashem needs to promise: "I will ordain My blessing." If he asks questions – then Hashem needs to ordain him with a special blessing. However, the people that are on a higher level of faith and trust in Hashem – do not ask questions. They rest assured that Hashem will provide them with everything they lack, and are therefore silent.

This is what the Midrash means when it writes: "he pays taxes and is silent." This person does not ask the question: "What will we eat in the seventh year?" These people are the "the strong warriors" who resemble the angels of grace, and it is about them that it is written: "the strong warriors who do His bidding, to obey the voice of His word"; first they do his bidding and then they obey his voice. They precede "we will do to we will obey," because they resemble the angels who have no choice but to obey the will of their Creator, who created them that way. Those of Am Yisrael who observe the shemita and do not ask questions resemble the angels because they place Hashem's will before their own while remaining silent.

In summary: The entire land belongs to Hashem, "Master of heaven and earth." Whatever wealth and property a person has was given to him by Hashem and there is no one who has any absolute private property. "Mine is the silver and mine is the gold – the word of Hashem, Master of legions" (Chaggai 2:8) If a person understands this, then it is not at all difficult for him to use his wealth to satisfy his Creator, whether they be mitzvot between man and heaven or they be mitzvot between men. He will stop having selfish worries and will place his trust entirely on Hashem, because He is the source of endless blessings.