Allah says in Surah al-Anfal, verse 51,
ذَٰلِكَ بِمَا قَدَّمَتْ أَيْدِيكُمْ وَأَنَّ ٱللَّهَ لَيْسَ بِظَلَّـٰمٍۢ لِّلْعَبِيدِ
That is for what your hands have put forth [of evil] and because Allāh is not ever unjust to [His] servants (‘abeed)."
And He says in Aal-’Imraan verse 30,
وَيُحَذِّرُكُمُ ٱللَّهُ نَفْسَهُۥ ۗ وَٱللَّهُ رَءُوفٌۢ بِٱلْعِبَادِ
And Allāh warns you of Himself, and Allāh is Kind to [His] servants (‘ibaad)."
Two different plurals have been used for the word ‘servant’ (عبد) - in the first verse Allah uses the word عبيد ‘abeed and in the second He uses the word عِباد ‘ibaad.
Its a common misconception that the plural for the word servant ‘abd عبد when used in reference to servants and worshippers of Allah is عِباد ‘ibaad, and that when used in reference to owned slaves and servants of people it is عبيد ‘abeed, but Allah’s usage in the Qur’an proves that this is not the case. So why two different words?
The difference between the usage of the words in the Qur’an, is actually not one of servitude to Allah vs servitude to the people, but rather it is actually related to the concept of free will.
As long as the servant is in this life, and choose willingly to submit to Allah and worship him - despite them having the freedom to obey and the freedom to disobey - Allah refers to them as his عِباد ‘ibaad.
But once this life has ended and Allah will strip people completely of their free will and choice, when they are forced to submit to Allah's retribution, to His punishment or reward, we see that He no longer refers to them "عباد" from them; at this point they are e considered عبيد rather than عباد - a term shared by all people, both believers and disbeleivers.
That is why the five verses in which the term "Abeed" is mentioned all pertain to the reckoning in the Hereafter.
So with this knowledge let us strive to ensure that we are of those who worship Allah freely, of our own desire and volition, and are of those whom Allah refers to as His عباد and not just as His عبيد.
And Allah knows best.