َ وَلَقَدْ كَذَّبَ الَّذِينَ مِنْ قَبْلِهِمْ فَكَيْفَ كَانَ نَكِيرِ ﴿۱۸﴾ أَوَلَمْ يَرَوْا إِلَى الطَّيْرِ فَوْقَهُمْ صَافَّاتٍ وَيَقْبِضْنَ مَا يُمْسِكُهُنَّ إِلَّا الرَّحْمَنُ إِنَّهُ بِكُلِّ شَيْءٍ بَصِيرٌ ﴿۱۹﴾ أَمَّنْ هَذَا الَّذِي هُوَ جُنْدٌ لَكُمْ يَنْصُرُكُمْ مِنْ دُونِ الرَّحْمَنِ إِنِ الْكَافِرُونَ إِلَّا فِي غُرُورٍ ﴿۲۰﴾

﴾18﴿ Wa laqad kazzabal lazeena min qablihim fakaifa kaana nakeer
﴾19﴿ Awalam yaraw ilat tairi fawqahum saaaffaatinw wa yaqbidn; maa yumsikuhunna il'lar rahmaan; innahoo bikulli shai im baseer
﴾20﴿ Amman haazal lazee huwa jundul lakum yansurukum min doonir rahmaan; inilkaafiroona illaa fee ghuroor

﴾18﴿ And indeed, those before them denied (the truth), so how was My punishment upon them
﴾19﴿ Do they not see the birds above them, spreading and folding their wings? None holds them except the Most Merciful. Indeed, He is All-Seeing of everything
﴾20﴿ But who is it that can be an army for you to help you besides the Most Merciful? The disbelievers are only in delusion

[18] To emphasize the worldly warning, it refers to the punishments of past nations and mentions their common reason, which is denial. (نَكِيرِ) comes from inkār (denial), and it means a punishment that is unprecedented and severe, as a form of expressing divine rejection.
[19] This is another intermediate rational proof, referring to birds—i.e., the intermediate blessings are mentioned. (الطَّيْرِ) – Refers to the species as a whole, and thus includes the plural; that's why the following pronouns refer back to it in the plural form. (فَوْقَهُمْ) – Refers to when birds are sitting above people, such as on the ground or in trees, though this specific quality (mentioned next) is not visible in that state. It becomes apparent when they are flying high in the air. (صَافَّاتٍ وَيَقْبِضْنَ) – These two states are mentioned: sometimes they spread their wings, and sometimes they fold them. (مَا يُمْسِكُهُنَّ إِلَّا الرَّحْمَنُ) – The word Rahman (the Most Merciful) indicates the general worldly blessings. In this exclusive phrasing, there is a clear proof that no one—not a prophet, saint, angel, jinn, or anyone else—has the power or control over this matter. A similar verse is mentioned in Surah An-Nahl (16:79).
[20] Since the polytheists believe in associating partners in blessings due to two hopes—one being the hope for help and support, and the other for provision—this refutes their belief, showing that both are solely under the control and power of Allah the Exalted.
So on what basis do you associate others with Allah in blessings?
Hence, this is a rebuke directed at the polytheists.
The meaning of (جُنْدٌ) is protectors or helpers (like an army or guards), and this corresponds to the belief of the polytheists.
(يَنْصُرُكُمْ مِنْ دُونِ الرَّحْمَنِ) – This phrase describes jund, meaning: if Allah the Exalted were to withhold His blessings from you and bring upon you calamities, could these gods remove your suffering or provide any blessing?
A similar question and answer appear in Surah Az-Zumar (39:38) and Surah Al-Mu’minun (23:88).
(إِنِ الْكَافِرُونَ إِلَّا فِي غُرُورٍ) – The delusion is that they believe these deities have power over benefit and harm for them, and that worshiping them brings them closer to Allah.