He has created man from a Nutfah, then behold, this same (man) becomes an open opponent.
Allah mentions how man has been created from a Nutfah, i.e., something that is insignificant, weak and has no value - but when man becomes independent and is able to fend for himself - then he begins to dispute with his Lord, may He be exalted, and disbelieves in Him and fights His Messengers.
But man was created to be a servant, not an opponent, as Allah says;
وَهُوَ الَّذِى خَلَقَ مِنَ الْمَأءِ بَشَراً فَجَعَلَهُ نَسَباً وَصِهْراً وَكَانَ رَبُّكَ قَدِيراً
وَيَعْبُدُونَ مِن دُونِ اللَّهِ مَا لَا يَنفَعُهُمْ وَلَا يَضُرُّهُمْ وَكَانَ الْكَـفِرُ عَلَى رَبِّهِ ظَهِيراً
And it is He Who has created man from water, and gave him descendants, and made Him kindred by marriage, and your Lord is capable (of all things).
And they worship besides Allah, that which can neither profit them nor harm them; and the disbeliever is ever a helper (of Shaytan) against his Lord. (25;54-55)
And;
أَوَلَمْ يَرَ الاِنسَـنُ أَنَّا خَلَقْنَـهُ مِن نُّطْفَةٍ فَإِذَا هُوَ خَصِيمٌ مٌّبِينٌ
وَضَرَبَ لَنَا مَثَلً وَنَسِىَ خَلْقَهُ قَالَ مَن يُحىِ الْعِظَـمَ وَهِىَ رَمِيمٌ
قُلْ يُحْيِيهَا الَّذِى أَنشَأَهَأ أَوَّلَ مَرَّةٍ وَهُوَ بِكُلِّ خَلْقٍ عَلِيمٌ
Does not man see that We have created him from Nutfah. Yet, behold he stands as an open opponent. And he puts forth for Us a parable, and forgets his own creation.
He says;"Who will give life to these bones after they are rotten and have become dust"
Say;"He will give life to them Who created them the first time! And He is the knower of every creature!" (36;77-79)
Imam Ahmad and Ibn Majah reported that Busr bin Jahhash said;
"The Messenger of Allah spat in his palm, then he said,
يَقُولُ اللهُ تَعَالَى
ابْنَ ادَمَ أَنَّى تُعْجِزُنِي وَقَدْ خَلَقْتُكَ مِنْ مِثْلِ هَذِهِ حَتَّى إِذَا سَوَّيْتُكَ فَعَدَلْتُكَ مَشَيْتَ بَيْنَ بُرْدَيْكَ وَلِلَْرْضِ مِنْكَ وَيِيدٌ
فَجَمَعْتَ وَمَنَعْتَ حَتَّى إِذَا بَلَغَتِ الْحُلْقُومَ قُلْتَ أَتَصَدَّقُ وَأَنَّى أَوَانُ الصَّدَقَة
Allah, may He be exalted, says;
"O son of Adam, how could you be more powerful than I when I have created you from something like this, and when I have fashioned you perfectly and made you complete, you walk wearing your two garments and the earth makes a sound (beneath your feet).
You collect money but do not give anything to anyone, then when the soul of a dying person reaches the throat, you say, `I want to give in charity', but it is too late for charity.