Word by Word Analysis

وَمِنَ ٱلنَّاسِ مَن يَعْبُدُ ٱللَّهَ عَلَىٰ حَرْفٍ ۖ فَإِنْ أَصَابَهُۥ خَيْرٌ ٱطْمَأَنَّ بِهِۦ ۖ وَإِنْ أَصَابَتْهُ فِتْنَةٌ ٱنقَلَبَ عَلَىٰ وَجْهِهِۦ خَسِرَ ٱلدُّنْيَا وَٱلْـَٔاخِرَةَ ۚ ذَٰلِكَ هُوَ ٱلْخُسْرَانُ ٱلْمُبِينُ 11

And of the people is he who worships Allāh on an edge. If he is touched by good, he is reassured by it; but if he is struck by trial, he turns on his face [to unbelief]. He has lost [this] world and the Hereafter. That is what is the manifest loss.