The Prophets
أَمْ لَهُمْ ءَالِهَةٌ تَمْنَعُهُم مِّن دُونِنَا ۚ لَا يَسْتَطِيعُونَ نَصْرَ أَنفُسِهِمْ وَلَا هُم مِّنَّا يُصْحَبُونَ
Or do they have gods to defend them other than Us? They are unable [even] to help themselves, nor can they be protected from Us.
Nearby ayahs help place verse 21:43 in sequence and meaning.
وَلَقَدِ ٱسْتُهْزِئَ بِرُسُلٍ مِّن قَبْلِكَ فَحَاقَ بِٱلَّذِينَ سَخِرُوا۟ مِنْهُم مَّا كَانُوا۟ بِهِۦ يَسْتَهْزِءُونَ
And already were messengers ridiculed before you, but those who mocked them were enveloped by what they used to ridicule.
قُلْ مَن يَكْلَؤُكُم بِٱلَّيْلِ وَٱلنَّهَارِ مِنَ ٱلرَّحْمَـٰنِ ۗ بَلْ هُمْ عَن ذِكْرِ رَبِّهِم مُّعْرِضُونَ
Say, "Who can protect you at night or by day from the Most Merciful?" But they are, from the remembrance of their Lord, turning away.
بَلْ مَتَّعْنَا هَـٰٓؤُلَآءِ وَءَابَآءَهُمْ حَتَّىٰ طَالَ عَلَيْهِمُ ٱلْعُمُرُ ۗ أَفَلَا يَرَوْنَ أَنَّا نَأْتِى ٱلْأَرْضَ نَنقُصُهَا مِنْ أَطْرَافِهَآ ۚ أَفَهُمُ ٱلْغَـٰلِبُونَ
But, [on the contrary], We have provided good things for these [disbelievers] and their fathers until life was prolonged for them. Then do they not see that We set upon the land, reducing it from its borders? So it is they who will overcome?
قُلْ إِنَّمَآ أُنذِرُكُم بِٱلْوَحْىِ ۚ وَلَا يَسْمَعُ ٱلصُّمُّ ٱلدُّعَآءَ إِذَا مَا يُنذَرُونَ
Say, "I only warn you by revelation." But the deaf do not hear the call when they are warned.