How can the Muslim intend his whole life to be for Allah?

Praise
be to Allah

The Muslim is
the one who submits to Allah, may He be glorified and exalted, and complies
with His laws and His commands and prohibitions, who worships Allah, may He
be exalted, because He is his Lord and Creator, Who is deserving of worship;
he believes in the existence and greatness of Allah and that He is
Self-Sustaining and the Sustainer of the universe. Thus belief in Allah will
fill his heart and control his thoughts; love of Allah will become his goal
in this life and the next, and he will hope that Allah will accept him among
His righteous slaves.

Allah, may He be
exalted, says (interpretation of the meaning):

“Say,
‘Indeed, my Lord has guided me to a straight path – a correct religion – the
way of Abraham, inclining toward truth. And he was not among those who
associated others with Allah.’

Say, “Indeed, my
prayer, my rites of sacrifice, my living and my dying are for Allah , Lord
of the worlds.

No partner has
He. And this I have been commanded, and I am the first [among you] of the
Muslims”

[al-An‘aam
6:161-163].

The one who
understands these meanings will strive to keep in mind the intention of
drawing closer to Allah, may He be glorified and exalted, in all aspects of
his life. So when he sleeps, he seeks reward for his sleep with Allah, may
He be glorified and exalted, because by sleeping and resting he will have
the energy to worship Allah when he wakes up. When he eats or drinks, he
intends thereby to have nourishment that will help him to fulfil his duty
towards Allah. When he gets married, he aims to keep himself chaste and to
be content with what is lawful so that he has no need of what is unlawful.
When he seeks to have children, he seeks to have righteous offspring who
will increase the number of those who adhere to the path of Allah. When he
speaks, he speaks for a good reason, and when he remains silent, he does so
to avoid saying anything bad. He seeks reward by spending on himself and his
family. When he learns, reads and studies, he seeks reward for that too.
Such are his intentions and aims in all his deeds.

Ibn Taymiyah
(may Allah have mercy on him) said: He should not do permissible deeds
except that which will help him to obey and worship Allah, and his intention
in doing these permissible deeds should be to gain energy to obey and
worship Allah. End quote.

Majmoo‘ al-Fataawa
(10/460-461).

In brief, this
is how the Muslim can intend his entire life and all his deeds to be for the
sake of Allah, and we can sum that up in the following two points:

i.                   

He should adhere
to Islamic teachings in his deeds, so he should not fail to do any
obligatory duty and he should not commit any infractions.

ii.                 

He should note
in his heart how he can connect this action – even if it is basically a
worldly matter – to reward and seeking to draw closer to Allah, may He be
exalted.

You can apply
this to your specific question about losing weight. Whoever wants to make
efforts to lose weight in order to maintain good health so that he can
perform obligatory deeds and do his duty towards Allah in a better manner,
or wants to make himself look good for his wife, so as to achieve happiness
and love between them, or wants to look better for people so that he will be
better accepted among them, and have a better relationship with them, these
are all good aims and one will be rewarded for that, in sha Allah.

But if this
permissible action is done with the intention of imitating some of the
disbelievers, or is done to make one attractive to girls, and other devilish
aims, then this is sinful and deserving of punishment.

The same applies
to all permissible matters; the one who does them will not be rewarded
unless he seeks reward thereby and is aiming to achieve a good purpose.

Ibn al-Haajj
(may Allah have mercy on him) said: Depending on intention, a permissible
deed may become recommended (mandoob). End quote.

Al-Madkhil
(1/21).

Ibn al-Qayyim
stated that the elite among those who are close to Allah are those for whom
permissible acts have become acts of worships and means of drawing closer to
Allah because of the intention behind them. In their case, permissible deeds
bring them closer to Allah. End quote.

Madaarij
as-Saalikeen
(1/107)

It is soundly
narrated from the Messenger (blessings and peace of Allah be upon him) that
he said to Sa‘d ibn Abi Waqqaas (may Allah be pleased with him): “You will
never spend on maintenance, seeking thereby the Countenance of Allah, but
you will be rewarded for it, even a morsel that you put in your wife’s
mouth.” Narrated by al-Bukhaari (56) and Muslim (1628).

Imam an-Nawawi
(may Allah have mercy on him) said, commenting on this hadith:

This indicates
that if a permissible thing is done with the intention of seeking the
pleasure of Allah, may He be exalted, it becomes an act of obedience and
worship, and he will be rewarded for it. The Prophet (blessings and peace of
Allah be upon him) highlighted this when he said, “even a morsel that you
put in your wife’s mouth,” because man finds pleasure with his wife and
enjoys permissible intimacy with her, and when he puts a morsel of food in
her mouth, that is usually a kind of playful and kind treatment, and
enjoying that which is permissible, which is something that is far removed
from acts of worship and matters of the hereafter, yet despite that, the
Prophet (blessings and peace of Allah be upon him) said that if he seeks the
pleasure of Allah, may He be exalted, by doing that, he will be rewarded for
it. So other matters are more likely to be deserving of reward, if he seeks
to please Allah, may He be exalted, by doing them.

That also
applies if a person does something that is basically permissible, and seeks
to please Allah, may He be exalted by doing it; he will be rewarded for
that. This is like eating with the intention of strengthening oneself to do
acts of obedience to Allah, may He be exalted, and sleeping in order to rest
so that he can get up and do acts of worship with energy, and enjoying
intimacy with his wife so that he can restrain himself and his gaze and so
on from unlawful things, and so that he can fulfil his wife’s rights, and
produce a righteous child. This is the meaning of the words of the Prophet
(blessings and peace of Allah be upon him), “And in the intimacy of one of
you [with his wife] there is sadaqah [charity].” And Allah knows best. End
quote.

Sharh Muslim
(11/77).

As-Suyooti (may
Allah have mercy on him) said:

One of the best
proofs that a person will attain reward by having a sound intention when
doing permissible things and customary practices is the words of the Prophet
(blessings and peace of Allah be upon him): “And each person will have what
he intended.” The one who does this will be rewarded, if he seeks thereby to
draw closer to Allah, but if he does not seek or intend that, then he will
have no reward. End quote.

Sharh as-Suyooti
‘ala an-Nasaa’i
(1/19).

And there are
many similar comments from the scholars concerning this matter.

See also the
answer to question no. 69960.

But you should
understand that what we have mentioned to you about the intention of growing
closer to Allah, may He be exalted, by means of what you do of permissible
things is not by way of obligation and compulsion, because if it were
obligatory and compulsory, it would not be permissible; rather it would be
obligatory, and a person would be sinning by not doing it.

As for the one
who does not intend anything except to fulfil his personal wishes, or
desire, or need, or to enjoy something that is permissible, there is no
blame on him for what he does, so long as he knows that this matter is
something that sharee‘ah has allowed and permitted. But he will not be
rewarded merely for doing that deed, just as there is no sin on him for
simply doing it.

And Allah knows
best.