وَهُوَ الَّذِي أَحْيَاكُمْ ثُمَّ يُمِيتُكُمْ ثُمَّ يُحْيِيكُمْ إِنَّ الْإِنسَانَ لَكَفُورٌ ﴿٦٦﴾

It is He, Who gave you life, and then will cause you to die, and will again give you life. Verily, man is indeed Kafurun.

This is like the Ayat:

كَيْفَ تَكْفُرُونَ بِاللَّهِ وَكُنتُمْ أَمْوَتًا فَأَحْيَـكُمْ ثُمَّ يُمِيتُكُمْ ثُمَّ يُحْيِيكُمْ ثُمَّ إِلَيْهِ تُرْجَعُونَ

How can you disbelieve in Allah Seeing that you were dead and He gave you life. Then He will give you death, then again will bring you to life and then unto Him you will return. (2:28)

قُلِ اللَّهُ يُحْيِيكُمْ ثُمَّ يُمِيتُكُمْ ثُمَّ يَجْمَعُكُمْ إِلَى يَوْمِ الْقِيَـمَةِ لاَ رَيْبَ فِيهِ

Say: "Allah gives you life, then causes you to die, then He will assemble you on the Day of Resurrection about which there is no doubt.'' (45:26)

قَالُواْ رَبَّنَآ أَمَتَّنَا اثْنَتَيْنِ وَأَحْيَيْتَنَا اثْنَتَيْنِ

They will say: "Our Lord! You have made us to die twice, and You have given us life twice!'' (40:11)

So how can you set up rivals to Allah and worship others besides Him when He is the One Who is independent in His powers of creation, provision and control of the existence!

وَهُوَ الَّذِي أَحْيَاكُمْ ...

It is He, Who gave you life,

means, He gave you life after you were nothing, and brought you into existence.

... ثُمَّ يُمِيتُكُمْ ثُمَّ يُحْيِيكُمْ ...

and then will cause you to die, and will again give you life.

means, on the Day of Resurrection.

... إِنَّ الْإِنسَانَ لَكَفُورٌ ﴿٦٦﴾

Verily, man is indeed Kafurun.

meaning, denying.