The Garden of Guidance.
Allah Almighty said:
"O you who have believed,
eat from the good things
which We have provided for you
and be grateful to Allah,
and be grateful to Allah,
if it is indeed Him
that you worship.
He has only forbidden you
carrion, blood,
the flesh of swine,
and that which has been dedicated
to other than Allah.
But whoever is forced by necessity, neither desiring it
nor transgressing,
there is no sin upon him.
Indeed, Allah is Forgiving
and Merciful."
And he, peace and blessings of Allah be upon him, said:
"O people,
Allah is Good,
and He accepts only what is good.
And indeed, Allah has commanded the believers
with that which He commanded the messengers,
for He said:
'O messengers,
eat from the good things
and work righteousness.'
“O ye messengers! Eat of the good things, and do right. Lo! I am Aware of what ye do.” (23:51)
And He said:
'O you who have believed,
eat from the good things
which We have provided for you.'"
[Then he mentioned] a man who travels on a long journey,
disheveled and dusty,
stretching out his hands to the sky:
"O Lord! O Lord!"
while his food is unlawful,
his drink is unlawful,
his clothing is unlawful,
and he has been nourished with what is unlawful—
how then could he be answered?
Related by Muslim.
A point of benefit:
In the verse, there is a command to consume what is lawful,
and in the hadith, there is an explanation
of a means by which supplication is answered,
derived by contrary implication.
For if consuming what is unlawful
is a reason for supplication not being answered,
then ensuring one's food is pure and wholesome—
meaning, eating what is lawful—
is a cause for its being answered,
and this is precisely what was mentioned in the hadith of Sa'd.