This verse is the (Jawab of the oath), that is, the sentence that follows the oath. Allah (swt) bestows favours on all mankind; He (swt) has created the universe and mankind, who is the main subject of the Message. Allah (swt) talked about forming and assembling of mankind in the best stature and talked about the stages of creation as well:

 وَلَقَدْ خَلَقْنَا الْإِنسَانَ مِن سُلَالَةٍ مِّن طِينٍ % ثُمَّ جَعَلْنَاهُ نُطْفَةً فِي قَرَارٍ مَّكِينٍ % ثُمَّ خَلَقْنَا النُّطْفَةَ عَلَقَةً فَخَلَقْنَا الْعَلَقَةَ مُضْغَةً فَخَلَقْنَا الْمُضْغَةَ عِظَامًا فَكَسَوْنَا الْعِظَامَ لَحْمًا ثُمَّ أَنشَأْنَاهُ خَلْقًا آخَرَ ۚ فَتَبَارَكَ اللَّهُ أَحْسَنُ الْخَالِقِينَ

(And certainly did We create man from an extract of clay. % Then We placed him as a sperm-drop in a firm lodging. % Then We made the sperm-drop into a clinging clot, and We made the clot into a lump [of flesh], and We made [from] the lump, bones, and We covered the bones with flesh; then We developed him into another creation. So blessed is Allah, the best of creators.) (Al-Muminoon: 12-14)

Allah (swt) created the mankind from clay then shaped him as He willed; Allah (swt) placed him as a sperm-drop in a firm lodging, then Allah (swt) developed this sperm-drop into another creation. Allah (swt) says: (We create) and does not say (We made) because He (swt) creates the sperm-drop, then He (swt) makes it into a clinging clot, then makes this into a lump then makes from the lump, bones, then covers the bones with flesh, at last, He (swt) develops him into another creation. This is all about the physical creation of mankind, whereas, the creation of mankind in the midst of life’s hardship and difficulties, Allah (swt) says:

 {لَقَدْ خَلَقْنَا الْإِنسَانَ فِي كَبَدٍ }

(We have certainly created man into hardship.) (Al-Balad: 4)

أَحْسَنِ تَقْوِيمٍ (the best of stature): Making something as it should be in composition; that means; this creature walks on two feet, while others walk on four, he has a straight shape with best stature and form. So blessed is Allah, the best of creators.

But are not the angels created in the best form? Are not they more beautiful than the human kind? The answer is: Yes, the angels are created in best form which suits their responsibilities, and the mankind as well, is created in the best form in convenience with other inferior creatures.