﴿ وَٱلَّذِينَ يُؤْتُونَ مَآ ءَاتَوا۟ وَّقُلُوبُهُمْ وَجِلَةٌ أَنَّهُمْ إِلَىٰ رَبِّهِمْ رَٰجِعُونَ ﴾

“and who give whatever they [have to] give with their hearts trembling at the thought that unto their Sustainer they must return:”

and who give what they give of voluntary alms and righteous deeds while their hearts tremble with awe fearful lest it not be accepted from them because the particle lām ‘for’ is taken as implied before annahum ‘that they’ they are going to return to their Lord —