وَمِنَ النَّاسِ مَنْ يَّعْبُدُ اللّٰهَ عَلٰى حَرْفٍۚ فَاِنْ اَصَابَهٗ خَيْرُ ِۨاطْمَـَٔنَّ بِهٖۚ وَاِنْ اَصَابَتْهُ فِتْنَةُ ِۨانْقَلَبَ عَلٰى وَجْهِهٖۗ خَسِرَ الدُّنْيَا وَالْاٰخِرَةَۗ ذٰلِكَ هُوَ الْخُسْرَانُ الْمُبِيْنُ ( الحج: ١١ )
Wa minan naasi mai ya'budul laaha 'alaa harfin fa in asaabahoo khairunit maanna bihee wa in asaabat hu fitnatunin qalaba 'alaa wajhihee khasirad dunyaa wal aakhirah; zaalika huwal khusraanul mubeen (al-Ḥajj 22:11)
And of the people is he who worships Allah 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. (Al-Hajj  : 11)
1 Mufti Taqi Usmani
And among men there is one who worships Allah (standing) on the verge: so if some good thing happens to him, he is satisfied with it, and if a trial befalls him, he turns his face back. He loses both this world and the Hereafter. That is the manifest loss.