Eat halaal food only
O you who have believed, eat from the good things which We have provided for you and be grateful to Allah if it is [indeed] Him that you worship.
Qur'aan 2:172
[Allah said], "O messengers, eat from the good foods and work righteousness. Indeed, I, of what you do, am Knowing.
Qur'aan 23:51
Abu Hurairah (May Allah be pleased with him) said:
The Messenger of Allah (sallallaahu alayhi wa sallam) said, "O people! Allah is Pure and, therefore, accepts only that which is pure. Allah has commanded the believers as He has commanded His Messengers by saying: 'O Messengers! Eat of the good things, and do good deeds.' [Qur'aan 23:51]
And He said: 'O you who believe (in the Oneness of Allah - Islamic Monotheism)! Eat of the good things that We have provided you..."' [Qur'aan 2:172]. Then he (sallallaahu alayhi wa sallam) made a mention of the person who travels for a long period of time, his hair is dishevelled and covered with dust. He lifts his hand towards the sky and thus makes the supplication: 'My Rubb! My Rubb!' But his food is unlawful, his drink is unlawful, his clothes are unlawful and his nourishment is unlawful, how can, then his supplication be accepted?"
Sahiih Muslim Hadiith No. 1015
"...eat from the good things..."
Regarding this portion Imaam al-Tabari writes in his Tafsiir
يعني: اطعَموا من حَلال الرزق الذي أحللناهُ لكم, فطاب لكم بتحليلي إياه لكم
Meaning eat of the halaal rizq which We have made Halaal for you.
As you can see from Imaam al-Tabari's explanation, the good things refers to what Allaah has made halaal for us. We are to eat and drink what is halaal. And all halaal things are good. They are good because Allaah called them good in the Qur'aan.
Reference(s):
Tafsiir al-Qurtubi
Volume 2 Page 215
Tafsiir al-Tabari
Volume 3 Page 317