Ask an Alim

In the Name of Allah, the All-Beneficent, the All-Merciful.
Wa-Alaykum Assalam Wa Rahmtu-Allah,

Allah SWT is limitless and the creator for Mercy and Forgiveness, he is the Ultimate Merciful One and Forgiver, how can He not forgive someone who repents and returns to Him.

The following ayahs wil be helpful in replying to your question:

1. إِنَّ اللَّـهَ لَا يَغْفِرُ أَن يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَٰلِكَ لِمَن يَشَاءُ ۚ وَمَن يُشْرِكْ بِاللَّـهِ فَقَدِ افْتَرَىٰ إِثْمًا عَظِيمًا ﴿٤٨﴾ – Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allah has certainly fabricated a tremendous sin. Holy Qur’an 4:48

Like wise: إِنَّ اللَّـهَ لَا يَغْفِرُ أَن يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَٰلِكَ لِمَن يَشَاءُ ۚ وَمَن يُشْرِكْ بِاللَّـهِ فَقَدْ ضَلَّ ضَلَالًا بَعِيدًا ﴿١١٦﴾ Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allah has certainly gone far astray. Holy Qur’an 4:116

This indicates that shirk is a grave, unforgivable sin.

However….

2. Th Holy Qur’an also states 4:17-18- إِنَّمَا التَّوْبَةُ عَلَى اللَّـهِ لِلَّذِينَ يَعْمَلُونَ السُّوءَ بِجَهَالَةٍ ثُمَّ يَتُوبُونَ مِن قَرِيبٍ فَأُولَـٰئِكَ يَتُوبُ اللَّـهُ عَلَيْهِمْ ۗ وَكَانَ اللَّـهُ عَلِيمًا حَكِيمًا ﴿١٧﴾ وَلَيْسَتِ التَّوْبَةُ لِلَّذِينَ يَعْمَلُونَ السَّيِّئَاتِ حَتَّىٰ إِذَا حَضَرَ أَحَدَهُمُ الْمَوْتُ قَالَ إِنِّي تُبْتُ الْآنَ وَلَا الَّذِينَ يَمُوتُونَ وَهُمْ كُفَّارٌ ۚ أُولَـٰئِكَ أَعْتَدْنَا لَهُمْ عَذَابًا أَلِيمًا ﴿١٨﴾ The repentance accepted by Allah is only for those who do wrong in ignorance [or carelessness] and then repent soon after. It is those to whom Allah will turn in forgiveness, and Allah is ever Knowing and Wise.But repentance is not [accepted] of those who [continue to] do evil deeds up until, when death comes to one of them, he says, “Indeed, I have repented now,” or of those who die while they are disbelievers. For them We have prepared a painful punishment. Holy Qur’an 4:17-18

In other words, Allah is all forgiving, and one must strive towards His forgiveness and mercy and not despair of His mercy, while fearing His punishment. As soon as you realise your mistake, you should immediately repent because إِنَّ اللَّـهَ يُحِبُّ التَّوَّابِينَ وَيُحِبُّ الْمُتَطَهِّرِينَ Indeed, Allah loves those who are constantly repentant and loves those who purify themselves. (Holy Qur’an 2:222)

The caution is that we must repent immediately and strengthen our faith and not return to shirk… ever – lest we die with this belief… for which it is not forgivable, and death may come upon us at any time and without warning.

This severe punishment falls upon those who إِنَّ الَّذِينَ آمَنُوا ثُمَّ كَفَرُوا ثُمَّ آمَنُوا ثُمَّ كَفَرُوا ثُمَّ ازْدَادُوا كُفْرًا لَّمْ يَكُنِ اللَّـهُ لِيَغْفِرَ لَهُمْ وَلَا لِيَهْدِيَهُمْ سَبِيلًا ﴿١٣٧﴾Indeed, those who have believed then disbelieved, then believed, then disbelieved, and then increased in disbelief – never will Allah forgive them, nor will He guide them to a way. Holy Qur’an 4:137

You should read the following from Greater Sins https://www.al-islam.org/greater-sins-volume-1-ayatullah-sayyid-abdul-husayn-dastghaib-shirazi/first-greater-sin-shirk and https://www.al-islam.org/greater-sins-volume-1-ayatullah-sayyid-abdul-husayn-dastghaib-shirazi/second-greater-sin-yas-despair which are about Shirk and Despair as the two first greater sins.

Hope that helps.

Regards
S.L.AlHakim.