No, lying does not break the fast. However, it does impact the reward of the fast.
عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ، قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: مَنْ لَمْ يَدَعْ قَوْلَ الزُّورِ وَالعَمَلَ بِهِ، فَلَيْسَ لِلَّهِ حَاجَةٌ فِي أَنْ يَدَعَ طَعَامَهُ وَشَرَابَهُ
(Sayidina) Abu Huraira (May Allah be pleased with him) said that the Messenger of Allah ﷺ said, ‘Whoever does not give up speaking falsehood and acting according to it, then Allah (Most High) is not in need of his leaving his food and his drink’. (Sahih al-Bukhari, 1903).
Some people misunderstand the Hadith above. They imagine that it means a person who engages in lying whilst fasting has nullified his fast, or such a person should refrain from fasting. Imam Ibn Hajr addressed this in his commentary.
وَالْمُرَادُ بِقَوْلِ الزُّورِ الْكَذِبُ وَالْجَهْلِ السَّفَهُ وَالْعَمَلِ بِهِ أَيْ بِمُقْتَضَاهُ كَمَا تَقَدَّمَ قَوْلُهُ فَلَيْسَ لِلَّهِ حَاجَةٌ فِي أَنْ يَدَعَ طَعَامه وَشَرَابه قَالَ بن بَطَّالٍ لَيْسَ مَعْنَاهُ أَنْ يُؤْمَرَ بِأَنْ يَدَعَ صِيَامَهُ وَإِنَّمَا مَعْنَاهُ التَّحْذِيرُ مِنْ قَوْلِ الزُّورِ. (فتح الباري شرح صحيح البخاري)
The meaning of Qowl al-Zoor is lying, ignorance, stupidity and acting according to it. It has already been mentioned that it refers to the dictates of it. His ﷺ saying, Allah (Most High) is not in need of his leaving his food and his drink, Ibn Bataal explained it does not mean that one should be commanded to refrain from fasting. Rather the meaning is one should be warned against speaking falsehood. (Imam Ibn Hajr al-Asqalani, Fath al-Bari).
So it is clear that it is unacceptable to suggest to a person who engages in sin whilst fasting that he should refrain from fasting. Rather he should be encouraged to fast but warned against the sin he is engaging in (see video below for more detail). This point has been emphasised by scholars of the Hanafi Madhab too.
وَقَالَ أَبُو عمر: لَيْسَ مَعْنَاهُ أَن يُؤمر بِأَن يدع صِيَامه، وَإِنَّمَا مَعْنَاهُ التحذير من قَول الزُّور. (عمدة القاري شرح صحيح البخاري)
Abu Umar said, it does not mean that one should be commanded to refrain from fasting. Rather the meaning is one should be warned against speaking falsehood. (Imam Badr al-Deen al-Ayni, Umdatu al-Qari).
The Hanafi scholars did not include lying as one of the nullifiers of the fast. This is due to the fact that lying and similar sins do not impact the legal validity (Sihah) of the fast, rather they impact the reward and acceptance. Unfortunately many Muslims have not studied Fiqh (which is Fard Ayn knowledge) and therefore cannot differentiate between legal validity and acceptance or reward. Such people regularly misunderstand Quran, Hadith and legal rulings. If every Muslim fulfilled his or her obligation of studying the Fard Ayn knowledge, then there would be far less confusion in the Ummah. Imam Ali al-Qari referred to this difference, between legal validity and acceptance when commentating upon the Hadith above.
فَإِنَّهُ لَا يَلْزَمُ مِنْ عَدَمِ الْقَبُولِ عَدَمُ الصِّحَّةِ بِخِلَافِ الْعَكْسِ. (مرقاة المفاتيح)
An action not being accepted does not necessitate it being legally invalid, as opposed to the opposite. (Imam Ali al-Qari, Mirqaat al-Mafateeh).
This issue must be studied thoroughly in Fiqh classes to truly understand it. However, a brief explanation is that legal validity is different to acceptance. Something can be legally valid but not accepted, due to a lack of sincerity or other factors. Meaning one fulfilled all of the legal requirements therefore the action does not need to be repeated. However, one has no reward for this action due to a lack of sincerity. Nevertheless, one has avoided the punishment of failing to fulfil an obligation.
It is also important to note that we do not usually make an absolute determination regarding acceptance, since that is with Allah Most High. As for validity, we do venture to make determinations regarding it, because it is based upon the revealed Sharia. So we simply apply the Sharia rulings to make a determination.
The Hadith above is better understood once a person appreciates the difference between legal validity and acceptance. So, a fast is not nullified by lying or similar sins. Therefore, one is not obliged to repeat the Fast. However, it does have a significant impact upon acceptance and reward.
And Allah Most High Knows Best.
-Answered by Shaykh Noorud-deen Rashid (08.04.2022)
Is the hadith “seeking knowledge is an obligation upon every Muslim” authentic?
See also video: