Question:
Oh Noble Shaykh, what is the purpose of the creation of Mankind?

Answer:
Prior to answering this question, I would like to bring attention upon a general principle that is connected to Allāh and what He decrees, and this principle is extracted from His speech سبحانه وتعالى:
وَهُوَ الْعَلِيمُ الْحَكِيمُ¹
He is the All-Knower, the All-Wise.²
إِنَّ اللَّهَ كَانَ عَلِيمًا حَكِيمًا³
Verily! Allah is Ever All-Knower, All-Wise.⁴

And there are many proofs upon the affirmation of the Wisdom of Allāh regarding that which He creates and that which He decrees. And verily there does not exist anything that Allāh creates except that there is wisdom for it, whether in fashioning it or in the administration of it. And there is not anything that He decrees (Allāh’s commandments) except that it is with (His) wisdom, whether in it’s obligation or prohibition or (in it’s) permissibility.
However, this Wisdom that encompasses His Universal Decree and Legislative Decree could be known to us and could be unknown (to all other than Allāh). Or it could be known to a few people as opposed to others, based on that which Allāh gives to them of knowledge.

With this acknowledgement, we say that verily Allāh created Mankind based on immense wisdom, and a praiseworthy purpose; and it is for His worship (alone). سبحانه وتعالى
وَمَا خَلَقْتُ الْجِنَّ وَالْإِنْسَ إِلَّا لِيَعْبُدُونِ⁵
And I (Allāh) created not the jinns and humans except they should worship Me (Alone).
أَفَحَسِبْتُمْ أَنَّمَا خَلَقْنَاكُمْ عَبَثًا وَأَنَّكُمْ إِلَيْنَا لَا تُرْجَعُون⁶
“Did you think that We had created you in play (without any purpose), and that you would not be brought back to Us?”⁷

And so on from verses that show that Allāh’s wisdom and purpose in the creation of Mankind is for His worship (alone).

¹Al-Quran [Surah At-Tahrim Ayat-2]
²Noble Quran- Surah At-Tahrim Ayat-2 [Muhsin Khan and Taqi-ud-Din al-Hilali]
³Al-Quran-[Surah Al-Ahzab, Ayat-1]
⁴Noble Quran- Surah Al-Ahzab Ayat-1 [Muhsin Khan and Taqi-ud-Din al-Hilali]
⁵Al- Quran [Surah Adh-Dhariyat, Ayat-56]
⁶Al- Quran [Surah Al-Mu’minun, Ayah-115]
⁷Noble Quran – Surah Surah Al-Mu’minun, Ayah-115 [Muhsin Khan and Taqi-ud-Din al-Hilali]
Jurisprudence of Worship- Fatwa For Sâum (Fasting) By: Shaykh Muhammad ibn Saalih ibn Uthaymeen رحمه الله تعالى (pg.11-12)

Translated by: Abu Uwais, Muhammad Abdullahi Elmi