The Messenger (blessings and peace of Allah be upon him) was the least interested of all people in worldly gain

The Messenger of Allah (blessings and peace of Allah be upon
him) was the least interested of all people in worldly gain, and his
asceticism was by choice. If he had wanted, Allah would have turned the
mountains into gold for him, and Allah, may He be exalted, enabled him to
conquer land and allocated to him one fifth of the booty as his due, and
half of the farmland of Khaybar became his… Yet he used to give in charity
all the wealth that came to him, and he continued to sleep on the ground and
not find anything to eat. 

When some people spoke about the division of booty, the
Prophet (blessings and peace of Allah be upon him) said: “I have nothing of
this booty except the khums [one-fifth that was allocated to him], and the
khums is returned to you.” Narrated by Abu Dawood (2694); classed as saheeh
by al-Albaani in Saheeh Abi Dawood. In other words, the Prophet
(blessings and peace of Allah be upon him) did not take for himself the one
fifth that was his due share of the booty; rather he used to give it in
charity to the Muslims. 

He (blessings and peace of Allah be upon him) used to say in
his supplication: “O Allah, make the provision of the family of Muhammad (no
more than) sufficient.” Muslim (1055). 

In other words, he asked Allah, may He be exalted, to grant
him provision that was just enough, and he (blessings and peace of Allah be
upon him) did not seek any more than that. 

There follow some of the hadiths which describe the
asceticism of the Prophet (blessings and peace of Allah be upon him) and his
lack of interest in worldly gain: 

It was narrated that ‘Aa’ishah (may Allah be pleased with
her) said: The Messenger of Allah (blessings and peace of Allah be upon him)
never ate his fill of wheat bread for three days in a row, until he passed
away. Narrated by al-Bukhaari (5374) and Muslim (2970). 

She (may Allah have mercy on her) also said: We used to look
at the new moon, then the new moon, then the new moon, three new moons in
two months, and no fire would be lit in the houses of the Messenger of Allah
(blessings and peace of Allah be upon him). She was asked: What did you live
on? She said: The two black ones, dates and water, but the Messenger of
Allah (blessings and peace of Allah be upon him) had some neighbours from
among the Ansaar and they had milch-animals; they would send some of their
milk to the Messenger of Allah (blessings and peace of Allah be upon him),
and he would give it to us to drink.

Narrated by al-Bukhaari (2567) and Muslim (2972) 

It was narrated from her (may Allah be pleased with her) that
she said: The Messenger of Allah (blessings and peace of Allah be upon him)
died when there was nothing on my shelf that a living being could eat except
a handful of barley.

Narrated by al-Bukhaari (3097) and Muslim (2973). 

And she (may Allah be pleased with her) said: When the
Messenger of Allah (blessings and peace of Allah be upon him) died, he had
not eaten his fill of bread and olive oil twice in one day.

Muslim (2974) 

It was narrated that an-Nu‘maan ibn Basheer (may Allah be
pleased with him) said: ‘Umar mentioned what people had got of worldly gains
and he said: I saw the Messenger of Allah (blessings and peace of Allah be
upon him) spending the whole day suffering because of hunger, and he could
not even find inferior-quality dates with which to fill his stomach.

Narrated by Muslim (2978) 

It was narrated from Anas ibn Maalik (may Allah be pleased
with him): The Prophet (blessings and peace of Allah be upon him) never ate
soft bread or a roasted sheep until he met Allah.

Narrated by al-Bukhaari (5385). 

It was narrated that Ibn ‘Abbaas (may Allah be pleased with
him) said: The Messenger of Allah (blessings and peace of Allah be upon him)
would remain hungry for several nights in a row, and his family would not be
able to find any supper, and most of their bread was barley bread.

Narrated by at-Tirmidhi (2360); classed as hasan by al-Albaani
in Saheeh at-Tirmidhi

It was narrated from Abu Hurayrah (may Allah be pleased with
him) that the Messenger of Allah (blessings and peace of Allah be upon him)
used to tie a stone to his stomach because of hunger. Narrated by Ibn al-A‘raabi
in al-Mu‘jam (21); classed as hasan by al-Albaani in as-Silsilah
as-Saheehah (1615) 

‘Amr ibn al-Haarith (may Allah be pleased with him) said: The
Prophet (blessings and peace of Allah be upon him) left nothing behind
except his weapon, his white mule and some land that he left behind as a
charity.

Narrated by al-Bukhaari (3098) 

It was narrated that ‘Abdullah ibn Mas‘ood (may Allah be
pleased with him) said: The Messenger of Allah (blessings and peace of Allah
be upon him) slept on a reed mat, and when he got up it had left marks on
his side. We said: O Messenger of Allah, why don’t we make a mattress for
you? He said: “I have no need of worldly comfort; I am in this world like
one who is on a journey, and halted to seek shade beneath a tree, then soon
moved on and left it.”

Narrated by at-Tirmidhi (2377); classed as saheeh by al-Albaani
in Silsilat al-Ahaadeeth as-Saheehah (438) 

The hadiths that speak of his asceticism and lack of interest
in worldly gain are too many to be counted, but what we have quoted here is
sufficient. 

And Allah knows best.