Al-Jawāb as-Sahīh li-man baddala dīn al-Masīh - Ibn Taimiya - (6/29)

Moreover, the Exalted says:

“I did not create jinn and humankind except to worship Me.” (adh-Dhāriyāt 51:56)

The noble end that perfects the children of Adam, secures their happiness, and guarantees their deliverance is to worship Allah alone. This is the very essence of the declaration, “There is no god but Allah.” For this purpose Allah sent all the messengers and revealed all the scriptures, and the human soul can never be sound, purified, or complete without it.

He, exalted, also says:

“And woe to the polytheists—those who do not give the zakah.” (Fussilat 41:6)

That is, they withhold what would purify their souls, namely pure monotheism and true faith.

Whoever fails to attain this sincerity will not be among the people of salvation and felicity, as the Exalted says:

“Indeed, Allah does not forgive that partners be ascribed to Him, but He forgives whatever is lesser than that for whomever He wills.” (an-Nisāʾ 4:48)

وَقَدْ قَالَ تَعَالَى: {وَمَا خَلَقْتُ الْجِنَّ وَالْإِنْسَ إِلَّا لِيَعْبُدُونِ} [الذاريات: ٥٦] فَالْغَايَةُ الْحَمِيدَةُ الَّتِي بِهَا يَحْصُلُ كَمَالُ بَنِي آدَمَ وَسَعَادَتُهُمْ وَنَجَاتُهُمْ عِبَادَةُ اللَّهِ وَحْدَهُ، وَهِيَ حَقِيقَةُ قَوْلِ الْقَائِلِ: لَا إِلَهَ إِلَّا اللَّهُ، وَلِهَذَا بَعَثَ اللَّهُ جَمِيعَ الرُّسُلِ، وَأَنْزَلَ جَمِيعَ الْكُتُبِ، وَلَا تَصْلُحُ النَّفْسُ وَتَزْكُو وَتَكْمُلُ إِلَّا بِهَذَا، كَمَا قَالَ تَعَالَى: {وَوَيْلٌ لِلْمُشْرِكِينَ الَّذِينَ لَا يُؤْتُونَ الزَّكَاةَ} [فصلت: ٦] أَيْ لَا يُؤْتُونَ مَا تَزْكُو بِهِ نُفُوسُهُمْ مِنَ التَّوْحِيدِ، وَالْإِيمَانِ. وَكُلُّ مَنْ لَمْ يَحْصُلْ لَهُ هَذَا الْإِخْلَاصُ لَمْ يَكُنْ مِنْ أَهْلِ النَّجَاةِ وَالسَّعَادَةِ كَمَا قَالَ تَعَالَى: {إِنَّ اللَّهَ لَا يَغْفِرُ أَنْ يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَلِكَ لِمَنْ يَشَاءُ} [النساء: ٤٨]