فَأَهْلَكْنَا أَشَدَّ مِنْهُم بَطْشًا
...
Then We destroyed men stronger than these,
means, `We destroyed those who disbelieved in the Messengers, and they were stronger in power than these who disbelieve in you, O Muhammad.'
This is like the Ayah:
أَفَلَمْ يَسِيرُواْ فِى الاٌّرْضِ فَيَنظُرُواْ كَيْفَ كَانَ عَـقِبَةُ الَّذِينَ مِن قَبْلِهِمْ كَانُواْ أَكْـثَرَ مِنْهُمْ وَأَشَدَّ قُوَّةً
Have they not traveled through the earth and seen what was the end of those before them? They were more in number than them and mightier in strength. (40:82)
And there are many similar Ayat.
...
وَمَضَى مَثَلُ الاَْوَّلِينَ
and the example of the ancients has passed away.
Mujahid said, "The way of their life."
Qatadah said, "Their punishment."
Others said,
"Their lesson," i.e., `We made them a lesson for those disbelievers who came after them, that they would suffer the same end as them,' as in the Ayah at the end of this Surah:
فَجَعَلْنَـهُمْ سَلَفاً وَمَثَلً لِّلٌّخِرِينَ
And We made them a precedent, and an example to later generations. (43:56)
سُنَّةَ اللَّهِ الَّتِى قَدْ خَلَتْ فِى عِبَادِهِ
this has been the way of Allah in dealing with His servants. (40:85)
وَلَن تَجِدَ لِسُنَّةِ اللَّهِ تَبْدِيلً
and you will not find any change in the way of Allah. (33:62)