[Q]: What should a fasting person do, and what is obligatory upon him?
[A]: “The fasting person must increase in obedience to Allaah, and to keep away from all the prohibited maters. It is obligatory upon the fasting person to safeguard the obligatory duties and to distance himself from all the prohibitions. So he should pray the five daily Prayers in their correct times and in congregation, and abandon lying, backbiting, cheating, dealing in usury, and all other prohibited matters. The Prophet (sallallaahu ’alayhi wa sallam) said: “Whosoever does not abandon falsehood in speech and action, then Allaah The Almighty and Majestic has no need that he should leave his food and drink. “ 
 Related by al-Bukhaaree (4/99). from Aboo Hurayrah (radiyallaahu ’anhu).  Answered by Shaykh Ibnul-’Uthaymeen in Haqeeqatus-Siyaam (pp.24-25).
TROID: Shaykh Ibn Baaz, Shaykh Ibnul-’Uthaymeen and the Committee of Major Scholars