Allah says,

مَا يُجَادِلُ فِي آيَاتِ اللَّهِ ...

None disputes in the Ayat of Allah,

One of the Attributes of the Disbelievers is That they dispute the Ayat of Allah -- and The Consequences of that Allah tells us that no one rejects or disputes His signs after clear proof has come,

... إِلَّا الَّذِينَ كَفَرُوا ...

but those who disbelieve,

i.e., those who reject the signs of Allah and His proof and evidence.

... فَلَا يَغْرُرْكَ تَقَلُّبُهُمْ فِي الْبِلَادِ ﴿٤﴾

So let not their ability of going about here and there through the land deceive you!

means, their wealth and luxurious life.

This is like the Ayah:

لاَ يَغُرَّنَّكَ تَقَلُّبُ الَّذِينَ كَفَرُواْ فِى الْبِلَـدِ

مَتَـعٌ قَلِيلٌ ثُمَّ مَأْوَاهُمْ جَهَنَّمُ وَبِئْسَ الْمِهَادُ

Let not the free disposal (and affluence) of the disbelievers throughout the land deceive you. A brief enjoyment; then, their ultimate abode is Hell; and worst indeed is that place for rest. (3:196-197)

نُمَتِّعُهُمْ قَلِيلاً ثُمَّ نَضْطَرُّهُمْ إِلَى عَذَابٍ غَلِيظٍ

We let them enjoy for a little while, then in the end We shall oblige them to (enter) a great torment. (31:24)

Then Allah consoles His Prophet Muhammad for the rejection of his people. He tells him that he has an example in the Prophets who came before him, may the blessings and peace of Allah be upon them all, for their nations disbelieved them and opposed them, and only a few believed in them.