Allah's Power and Ability over what is Greater than Resurrection
Allah the Exalted notifies the servants of His infinite power, which He demonstrated by creating what is bigger than that which they wondered about and whose possibility they discount,
(Have they not looked at the heaven above them, how We have made it and adorned it,) with lamps;
وَمَا لَهَا مِن فُرُوجٍ
(and there are no Furuj in it) i.e., clefts, according to Mujahid. Others said that Furuj means, rifts, or cracks. All these meanings are close to one another. Allah the Exalted and Most Honored said,
After mentioning the confused state of the infidels, Allah draws man's attention to His infinite power which He demonstrated by creating what is bigger than that which they wondered about and whose possibility they discounted. Referring to the heaven, the Qur'an says: وَمَا لَهَا مِن فُرُوجٍ (...and it has no cracks...50:6). Lexically, the word furuj is the plural of farj which means a crack, or an opening. This and the following few verses draw attention to the marvels of Allah's creation, the wonderful design in the universe, and to the flawless celestial firmament. If this was made by man there would have been patches, cracks, clefts or rifts. But no one can find any sort of patchwork or stitching in the sky. This, however, does not negate the existence of doors in the heaven. A door is not referred to as a crack:
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 11–14
The meaningfulness of the universe, its creative wisdom, its being free of shortcomings, and its being consistent with human needs compel every thinking and rational man to accept the sublimity of creation, and one who gives serious consideration to the system of the universe, will find the Creator in His creations. He will see a glimpse of the other world (the Hereafter) in this world, because, in fact, the world of the Hereafter is essentially another, more superior form of the present world.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.