Al-Aʿrāf: 141
{يَسُومُونَكُمْ سُوءَ الْعَذَابِ}
They inflict upon you the worst of the torment. It is derived from sāma al-silʿah (to seek a commodity), meaning they seek to impose severe torment upon you.
If you ask: What is the grammatical position of yasūmūnakum?
I say: It is an istiʾnāf (a new sentence) and has no grammatical position. It is also permissible for it to be a ḥāl (state) describing those addressed [the Children of Israel] or those describing the family of Pharaoh.
{ذَلِكُمْ}
This is a reference to the deliverance or to the torment.
{الْبَلَاءُ}
It means either the blessing or the trial.
{يُقَتِّلُونَ}
It is recited with the takhfīf (lightening of the tashdīd).
Al-Aʿrāf: 142
{وَوَاعَدْنَا مُوسَىٰ ثَلَاثِينَ لَيْلَةً وَأَتْمَمْنَاهَا بِعَشْرٍ فَتَمَّ مِيقَاتُ رَبِّهِ أَرْبَعِينَ لَيْلَةً ۚ وَقَالَ مُوسَىٰ لِأَخِيهِ هَارُونَ اخْلُفْنِي فِي قَوْمِي وَأَصْلِحْ وَلَا تَتَّبِعْ سَبِيلَ الْمُفْسِدِينَ}