السلام عليكم ورحمة الله
I apologise for the reverse order of answering, but I am finding the others difficult:
فَلَهُمْ - (And)So for them
أَجْرُهُمْ - their reward
عِندَ - (is) with
رَبِّهِمْ - their Lord
وَلا - and no
خَوْفٌ - fear (is)
عَلَيْهِمْ - upon them*
وَلا - and (are) not*
هُمْ - they
يَحْزَنُونَ - grieving
*According to the Hans Wehr Dictionary, the word خَوْفٌ (Fear) followed by the preposition عَلَى renders the meaning 'fearing for', thus, instead of translating وَلا خَوْفٌ عَلَيْهِمْ as 'and no fear (is) upon them,' the translation would be 'and no fearing for them', i.e. I think that means, they should not be in fearing (punishment), nor should anyone fear for them.
* I thought that unlike the first لاَ, this one was rather confusing. As the لاَ is not placed before the verb يَحْزَنُونَ ( they are grieving, they grieve - rendered from the past tense حَزَنَ [he grieved]) then perhaps the لاَ is not negating the action but rather confirming it, e.g. no grieving is for them (perhaps they are free from wrongdoing) yet a rhetorical question is posed; do they not grieve still - in gratitude?
However, then I pondered more and felt that the لاَ can also be that of negation as the sentence, هُمْ يَحْزَنُونَ (they [are] grieving) is in fact in the present tense, and لاَ as we have been taught is the particle for present-tense negation. So perhaps it IS saying 'And they (are) NOT greiving', this seems like the most relevant meaning, (but the other translation may also be valid as the prophet ص , though he was aquitted of all past and present sins, it did not stop his grievance for mankind and endless gratitude in lengthy prayers).
I look forward to some clarification إن شا الله
مع السلامة