Some of the things that the believer must safeguard are his head and stomach. Ibn Masud reports that the Messenger of Allah, may Allah’s peace and blessings be upon him, said,
“Being shy before Allah as is truly deserving is to safeguard the head and what it retains and the stomach and what it contains.” (Ahmad, Tirmidhi)
Safeguarding the head and what it retains includes safeguarding the hearing, seeing and tongue from falling into the prohibited. Safeguarding the stomach and what it contains includes safeguarding the heart from persisting in the proscribed. Allah has mentioned all of this in His saying,
“The hearing, the sight and the heart – each of these will be questioned.” (al-Isra’ 17:36)
Safeguarding the stomach and what it contains includes safeguarding it from consuming unlawful food and drink.
The Legacy of the Prophet Ibn Rajab Al-Hanbali p28-29