Who is the fasting person?

Imaam Ibnul Qayyim (رحمه الله) said:

The fasting person is the one whose limbs abstains from sins, his tongue (abstains) from lying, lewdness & false speech, his stomach (abstains) from food & drink & his private parts (abstain) from obscenity. When he speaks, he does not speak with what harms his fasting, & when he acts he does not do what corrupts his fasting. All his speech comes out useful & righteous.

Likewise his actions are of the status of that scent that is smelled by the one who sits with the seller of musk, & likewise the one who sits with the fasting person is benefitted by sitting with him & is saved from false speech, lies, evil deeds & oppression. This is the legislated fasting & not merely abstaining from food & drink^.[1] And it is (reported) in the authentic hadeeth: 

”Whoever does not give up lying speech (false statements) & acting on those lies & evil actions etc., Allaah is not in need of his leaving his food & drink.” ^[2]

Imaam Abdul Azeez Bin Baaz (rahimahullaah) also said: 

”In this (hadeeth) is a warning against being lackadaisical in the affair of fasting, & in another (version of this) narration the word ‘Jahl’ [ignorance, is mentioned & it means) 'Dhulm' (oppression).'' ^[3]

References:

[1] Sharh Al-Waabilus Sayyib of Imaam Abdul-Azeez Bin Baaz (rahimahullaah), page:31]
[2] English Translation of Saheeh Bukhaari, vol 3, Hadeeth Number: 1903. Muhsin khan
[3] Al-Hulalul Ibreeziyyah Min At-taleeqaat Al-Baaziyyah Alaa Saheeh Al-Bukhaari Vol:2, page:121, footnote number:4]

[Abu Mu-aawiyyah (Abdullaah Al-Gambi)]