﴿ وَمَن جَٰهَدَ فَإِنَّمَا يُجَٰهِدُ لِنَفْسِهِۦٓ ۚ إِنَّ ٱللَّهَ لَغَنِىٌّ عَنِ ٱلْعَٰلَمِينَ ﴾

“Hence, whoever strives hard [in God’s cause] does so only for his own good: for, verily, God does not stand in need of anything in all the worlds!”

Please check ayah 29:7 for complete tafsir.