Allah informs that He has revealed the Book to His servant and Messenger Muhammad -- may Allah's blessings be upon him until the Day of Judgement. Allah then describes Himself as being of unimaginable glory, possessing ultimate wisdom in His statements and actions. Allah then says,

[مَا خَلَقْنَا السَّمَـوَتِ وَالاٌّرْضَ وَمَا بَيْنَهُمَآ إِلاَّ بِالْحَقِّ]

(We created not the heavens and the earth and all that is between them except in truth,) meaning, not in idle play and falsehood.

[وَأَجَلٌ مُّسَمًّى]

(and for a specified term.) meaning, for a fixed and specified duration that will not increase or decrease. Allah continues,

[وَالَّذِينَ كَفَرُواْ عَمَّآ أُنذِرُواْ مُعْرِضُونَ]

(But those who disbelieve, turn away from that of which they are warned.) Meaning, the disbelievers are distracted from what is intended for them. Allah has indeed revealed to them a Book and sent to them a Messenger. Yet, they obstinately turn away from all of that. Therefore, they will soon realize the consequence of their behavior.