In verse 6, it was said: وَأَنزَلَ لَكُم مِّنَ الْأَنْعَامِ ثَمَانِيَةَ أَزْوَاجٍ (and sent down for you eight pairs of the cattle.). The creation of the cattle has been expressed in this verse by saying that they have been 'sent down from the skies' whereby an indication has been given that a major factor in their creation is water that is sent down from sky. Therefore, it can be said that these too were as if sent down from the skies. The noble Qur'an has used the same expression for human dress: أَنزَلْنَا عَلَيْكُمْ لِبَاسًا (We have sent down to you clothing - A1-A` raf, 7:26). Then, this word also appears in relation to some minerals, for instance, iron: وَأَنزَلْنَا الْحَدِيدَ j (and We sent down iron - Al-Hadid, 57:25). The purpose is to emphasize that these things were created through the intrinsic power of Allah Ta’ ala, and that they were given to human beings as His blessings. (Qurtubi)
Towards the later part of verse 6, it was said: خَلْقًا مِّن بَعْدِ خَلْقٍ فِي ظُلُمَاتٍ ثَلَاثٍ (He creates you in the wombs of your mothers, creation after creation, in three layers of darkness.) Here, some clues to the mysteries of Divine power that work in the creation of man have been released. First of all, it was well within the power of Allah Ta’ ala that He could have made the infant come to be created whole and complete in the womb of the mother within a single instant. But, such was the dictate of wisdom and expedient consideration that it was not done. Instead, a process of gradualness was opted for as indicated by: خَلْقًا مِّن بَعْدِ خَلْقٍ (creation after creation). The purpose was to ensure that the woman in whose womb this 'mini universe' was taking shape should gradually become used to bearing its burden. Secondly, the creation of this matchless marvel of beauty and efficiency provided with hundreds of precision gadgets, hair-thin veins to carry life-blood and spiritual input was not to look like things created by common industrialists in spacious factories under glowing lights. Instead of that, this marvel of creation has reached its completion at a place shielded by three layers of darkness, a location so hidden from night that it beats all imagination. فَتَبَارَكَ اللَّـهُ أَحْسَنُ الْخَالِقِينَ (glorious is Allah, the best of the Creators – Al-mu’ minun, 23:14).