✅ Answer: Refer to the following narrations:

1 الْفَضْلِ بْنِ شَاذَانَ عَنِ الرِّضَا أَنَّهُ كَتَبَ إِلَى الْمَأْمُونِ في كِتَابٍ و صِيَامُ شَهْرِ رَمَضَانَ فَرِيضَةٌ يُصَامُ لِلرُّؤْيَةِ و يُفْطَرُ لِلرُّؤْيَة

📚 ʿUyūn Akhbār al-Riḍā, vol. 2, p. 124

Imam al-Riḍā (peace be upon him) wrote in a letter to Ma'mun: Fasting in the month of Ramadan is an obligation; it begins with sighting (the crescent) and ends with sighting!

2 أَبِي أَيُّوبَ الْخَرَّازِ عَنْ أَبِي عَبْداللَّه في حَدِيثٍ قَالَ: إِنَّ شَهْرَ رَمَضَانَ فَرِيضَةٌ مِنْ فَرَائِضِ اللَّهِ عَزَّوَجَلَّ

📚 Tahdhīb, vol. 4, p. 160

Imam al-Sadiq (peace be upon him) said: Indeed, the month of Ramadan is one of Allah’s obligations!

3 عن يونس بن حماد الرازي قال سَمِعْتُ أَبَا عَبْداللَّه يَقُولُ مَنْ أَفْطَرَ يَوْماً مِنْ شَهْرِ رَمَضَان خَرَجَ رُوحُ الْإِيمَانِ مِنْهُ

📚 ʿIqāb al-Aʿmāl, p. 281

Yunus said: I heard Imam al-Sadiq (peace be upon him) say: Whoever breaks the fast of one day in Ramadan, the spirit of faith departs from him!

4 عن بريد العجلي قال: سُئِلَ أَبُو جَعْفَر عَنْ رَجُلٍ شَهِدَ عَلَيْهِ شُهُودٌ أَنَّهُ أَفْطَرَ مِنْ شَهْرِ رَمَضَانَ ثَلَاثَةَ أَيَّامٍ قال يُسْأَلُ هَلْ عَلَيْكَ فِي إِفْطَارِكَ إِثْمٌ فَإِنْ قَالَ لَا فَإِنَّ عَلَى الْإِمَامِ أَنْ يَقْتُلَهُ و إِنْ قَالَ نَعَمْ فَإِنَّ عَلَى الْإِمَامِ أَنْ يَنْهَكَهُ ضَرْباً

📚 al-Kāfī, vol. 4, p. 103

Burayd said: Imam al-Baqir (peace be upon him) was asked about a person against whom witnesses testified that he broke his fast three days in Ramadan. The Imam said: He is asked, ‘Do you believe there is sin in breaking the fast?’ If he says, ‘No,’ then it is upon the Imam to execute him. If he says, ‘Yes,’ then the Imam must punish him severely!

5 عن سماعة قال: سَأَلْتُهُ عَنْ رَجُلٍ وُجِدَ فِي شَهْرِ رَمَضَانَ وَ قَدْ أَفْطَرَ ثَلَاثَ مَرَّاتٍ وَ قَدْ رُفِعَ إِلَى الْإِمَامِ ثَلَاثَ مَرَّاتٍ قَالَ يُقْتَلُ فِي الثَّالِثَة

📚 al-Kāfī, vol. 4, p. 103

Samaʿah said: I asked the Imam (peace be upon him) about a man who was found breaking the fast in Ramadan three times and brought before the Imam three times. The Imam said: The third time, he is killed!

6 عن عبدالرَّحِيمِ الْقَصِيرِ عَنْ أَبِي عَبْداللَّه فِي حَدِيثٍ أَنَّهُ كَتَبَ إِلَيْهِ مَعَ عَبْدالْمَلِكِ بْنِ أَعْيَنَ سَأَلْتَ رَحِمَكَ اللَّهُ عَنِ الْإِيمَانِ و الْإِيمَانُ هُوَ الْإِقْرَارُ إِلَى أَنْ قَالَ و الْإِسْلَامُ قَبْلَ الْإِيمَانِ و هُوَ يُشَارِكُ الْإِيمَانَ فَإِذَا أَتَى الْعَبْدُ بِكَبِيرَةٍ مِنْ كَبَائِرِ الْمَعَاصِي أَوْ بِصَغِيرَةٍ مِنْ صَغَائِرِ الْمَعَاصِي الَّتِي نَهَى اللَّهُ عَنْهَا كَانَ خَارِجاً مِنَ الْإِيمَانِ سَاقِطاً عَنْهُ اسْمُ الْإِيمَانِ و ثَابِتاً عَلَيْهِ اسْمُ الْإِسْلَامِ فَإِنْ تَابَ و اسْتَغْفَرَ عَادَ إِلَى دار الْإِيمَانِ و لَا يُخْرِجُهُ إِلَى الْكُفْرِ إِلَّا الْجُحُودُ و الِاسْتِحْلَالُ أَنْ يَقُولَ لِلْحَلَالِ هَذَا حَرَامٌ وَ لِلْحَرَامِ هَذَا حَلَالٌ وَ دَانَ بِذَلِكَ فَعِنْدَهَا يَكُونُ خَارِجاً مِنَ الْإِسْلَامِ وَ الْإِيمَانِ وَ دَاخِلًا فِي الْكُفْر

📚 al-Kāfī, vol. 2, p. 27

Imam al-Sadiq (peace be upon him) wrote to ʿAbd al-Raḥīm al-Qaṣīr with ʿAbd al-Malik: May Allah have mercy on you! You asked about faith, and faith is confession… until he said: Islam precedes faith and is partnered with it. When a servant commits a major sin or a minor sin from those Allah has prohibited, he exits faith, and the name of faith is lifted from him, while the name of Islam remains. If he repents and seeks forgiveness, he returns to faith. He is only taken out of Islam and faith and into disbelief if he denies (the obligation) and declares the unlawful lawful — by saying of the lawful, ‘This is unlawful,’ and of the unlawful, ‘This is lawful,’ and holding to it. At that point, he exits Islam and faith and enters disbelief…!

✅ According to the above narrations and others: Fasting in Ramadan is a major divine obligation. If one abandons it without excuse but acknowledges it as a sin, the spirit of faith departs from him. If he is brought before the Imam three times for this, he is punished each time, and on the third time, he is executed.

But if he denies the obligation of fasting in Ramadan and considers breaking it lawful, he exits Islam and faith. If he is brought before the Imam in this state, he is executed.