29:6
وَمَن جَاهَدَ فَإِنَّمَا يُجَاهِدُ لِنَفْسِهِ إِنَّ اللَّهَ لَغَنِيٌّ عَنِ الْعَالَمِينَ
And if any strive (with might and main), they do so for their own souls: for Allah is free of all needs from all creation.
64:6
ذَلِكَ بِأَنَّهُ كَانَت تَّأْتِيهِمْ رُسُلُهُم بِالْبَيِّنَاتِ فَقَالُوا أَبَشَرٌ يَهْدُونَنَا فَكَفَرُوا وَتَوَلَّوا وَّاسْتَغْنَى اللَّهُ وَاللَّهُ غَنِيٌّ حَمِيدٌ
That was because there came to them messengers with Clear Signs, but they said: "Shall (mere) human beings direct us?" So they rejected (the Message) and turned away. But Allah can do without (them): and Allah is free of all needs, worthy of all praise.
80:7
وَمَا عَلَيْكَ أَلَّا يَزَّكَّى
Though it is no blame to thee if he grow not (in spiritual understanding).