These are ayas of a Holy Scripture from an age when these teachings were considered heretical on the other part of the world. It took several hundreds of years for the truth of Quran to be justified after autopsies of corpses dug out from cemeteries secretly and after medical practices certified it.

O mankind! if ye have a doubt about the Resurrection, (consider) that We created you out of dust, then out of sperm, then out of a leech-like clot, then out of a morsel of flesh, partly formed and partly unformed, in order that We may manifest (our power) to you; and We cause whom We will to rest in the wombs for an appointed term, then do We bring you out as babes, then (foster you) that ye may reach your age of full strength; and some of you are called to die, and some are sent back to the feeblest old age, so that they know nothing after having known (much), and (further), thou seest the earth barren and lifeless, but when We pour down rain on it, it is stirred (to life), it swells, and it puts forth every kind of beautiful growth (in pairs). (Quran 22:5)

If they really have doubts in their minds about the life after death, they have only to turn their attention either to their own nature, or to the nature around. How wonderful is their own physical growth, from lifeless matter, to seed, fertilised ovum, foetus, child youth, age, and death! How can they doubt that the Author of all these wonderful stages in their life here can also give them another kind of life after the end of this life? Or, if they look at external nature, they see the earth dead and barren and Allah's fertilising showers bring it in to life, growth and beauty in various forms. The Creator of this great pageant of Beauty can surely create yet another and a newer world.

Man We did create from a quintessence (of clay); (Quran 23:12)

In this beautiful passage, Allah's creative work, as far as man is concerned, is recapitulated, in order to show man's real position in this life, and the certainty of the future. Here we are not concerned with the earliest stage, the creation of primeval matter out of nothing. It is also a process of creation when inorganic matter becomes living matter. Thus inorganic constituents of the earth are absorbed into living matter by way of food and living matter reproduces itself by means of sperm. This is deposited in the ovum and fertilises it and rests for a time in security in the mother's womb. The first change in the fertilised ovum is the conversion into a sort of clot of thickly congealed blood; the zygote cells grow by segmentation; then the mass gradually assumes shape in its growth as a foetus.
From the lump develop bones and flesh and organs and a nervous system. So far man's growth is like that of an animal, but a further process takes place which makes the infant animal into the infant man. This is the breathing from Allah's spirit into him (15:29). It may be a continuous process parallel to that of physical growth. The child is born; it grows; it decays and dies; but after death another chapter opens for the individual, and it is to remind us of this most momentous chapter that the previous stages are recapitulated.

Then We placed him as (a drop of) sperm in a place of rest, firmly fixed; (Quran 23:13)

Then We made the sperm into a clot of congealed blood; then of that clot We made a (foetus) lump; then we made out of that lump bones and clothed the bones with flesh; then we developed out of it another creature. So, blessed be Allah, the best to create! (Quran 23:14)

After that, at length ye will die (Quran 23:15)

Our physical death in this mortal life seems to make a break. But if it were the end of all, our life becomes meaningless. Our own instinct tells us that it cannot be so, and Allah assures us that there will be a resurrection for judgment.

Again, on the Day of Judgment, will ye be raised up. (Quran 23:16)