The One Unforgiveable Sin is Shirk

Associating other deities with Allah is the one unforgiveable sin in Islam.

Allah T'ala says in the Holy Quran:

إِنَّ اللّهَ لاَ يَغْفِرُ أَن يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَلِكَ لِمَن يَشَاء وَمَن يُشْرِكْ بِاللّهِ فَقَدِ افْتَرَى إِثْمًا عَظِيمًا

004.048 God forgives not that partners should be set up with Him; but He forgives
anything else, to whom He pleases; to set up partners with God is to devise a sin
Most heinous indeed.

The purpose of this verse is not to tell man that he may commit any sin as long as he does not associate others with God in His divinity. The object is rather to impress upon those who had begun to regard polytheism as a trivial matter that it constitutes the most serious offence in God's sight, an offence so serious that while other sins may be pardoned this will not.

The Arabic word Shirk can be translated as polytheism. Polytheism should be understood in the light of the Islamic Holy texts.

From: Muhammad

There are Six wev for Get Allah!

There are many places in the Holy Quran, where the verses speak about the attributes of the ones who want success in this life and the hereafter. The first such place is in Surah Al-Baqarah, the second chapter.

The six qualities mentioned in these verses are:

Accept the Holy Quran as the Book of guidance as a God-conscious person

1. Belief in the unseen
2. Offer and establish prayer
3. Spend in the way of Allah from what He has given
4. Believe in the Holy Quran and the divine books sent to earlier Prophets of God
5. Believe in the After Life.

The verses and their explanation follow:

ذَلِكَ الْكِتَابُ لاَ رَيْبَ فِيهِ هُدًى لِّلْمُتَّقِينَ

الَّذِينَ يُؤْمِنُونَ بِالْغَيْبِ وَيُقِيمُونَ الصَّلاةَ وَمِمَّا رَزَقْنَاهُمْ يُنفِقُونَ

والَّذِينَ يُؤْمِنُونَ بِمَا أُنزِلَ إِلَيْكَ وَمَا أُنزِلَ مِن قَبْلِكَ وَبِالآخِرَةِ هُمْ يُوقِنُونَ

أُوْلَـئِكَ عَلَى هُدًى مِّن رَّبِّهِمْ وَأُوْلَـئِكَ هُمُ الْمُفْلِحُونَ

This is the Book; in it is guidance sure, without doubt, to those who fear God; Who believe in the Unseen, are steadfast in prayer, and spend out of what We have provided for them; And who believe in the Revelation sent to thee, and sent before thy time, and (in their hearts) have the assurance of the Hereafter. They are on (true) guidance, from their Lord, and it is these who will prosper. (Translation by Abdullah Yusuf Ali)

Allah T'ala says in the Holy Quran:

وَقَالَ الشَّيْطَانُ لَمَّا قُضِيَ الأَمْرُ إِنَّ اللّهَ وَعَدَكُمْ وَعْدَ الْحَقِّ وَوَعَدتُّكُمْ فَأَخْلَفْتُكُمْ وَمَا كَانَ لِيَ عَلَيْكُم مِّن سُلْطَانٍ إِلاَّ أَن دَعَوْتُكُمْ فَاسْتَجَبْتُمْ لِي فَلاَ تَلُومُونِي وَلُومُواْ أَنفُسَكُم مَّا أَنَاْ بِمُصْرِخِكُمْ وَمَا أَنتُمْ بِمُصْرِخِيَّ إِنِّي كَفَرْتُ بِمَآ أَشْرَكْتُمُونِ مِن قَبْلُ إِنَّ الظَّالِمِينَ لَهُمْ عَذَابٌ أَلِيمٌ

(14:22) And when Our judgment has been passed, Satan will say, "The fact is that the promises Allah had made with you were all true. I, too, made some promises with you but I failed to keep any of them.

• Yet I had no power over you; I did nothing but to invite you to my way and you accepted my invitation.
• So do not now blame me, but blame yourselves. I cannot help you here, nor can you help me. I dissociate myself from your making me a partner with God before this.
• Such wrong-doers are sure to receive a grievous torment.