What does it mean that God created mankind only to worship Him?

Wa alykum as-salaam,

This is a really interesting question and I think that Muhammad Asad’s Tafseer on this ayah (51:56) answers this question in a very concise and clear way, but first let’s take a look at the entire ayah for those who unfamiliar:

“And [tell them that] I have not created the invisible beings and men to any end other than that they may [know and] worship Me.”

Asad’s Tafseer explains this ayah in the following:

Thus, the innermost purpose of the creation of all rational beings is their cognition (ma’rifah) of the existence of God and, hence, their conscious willingness to conform their own existence to whatever they may perceive of His will and plan: and it is this twofold concept of cognition and willingness that gives the deepest meaning to what the Qur’an describes as “worship” (‘ibadah). As the next verse shows, this spiritual call does not arise from any supposed “need’ – on the part of the Creator, who is self-sufficient and infinite in His power, but is designed as an instrument for the inner development of the worshipper, who, by the act of his conscious self-surrender to the all-pervading Creative Will, may hope to come closer to an understanding of that Will and, thus, closer to God Himself.

I hope this answers your question, insha Allah.

I pray this reaches you and your families in the best of health and Iman, insha Allah.