«إِنِّي مَا قَتَلْتُ ابْنَكَ سَهْوًا وَلَا عَمْدًا»
I did not kill your son, either inadvertently or intentionally.
Sahwan wa-lā ʿamdan denies two categories of alleged action: inadvertent and deliberate. The elder seeks a more exhaustive wording than a simple “I did not do it.”
Innī mā qataltu negates the past action, with the two adverbial terms clarifying the scope of the denial. The formula is still a demanded statement within a dispute. Its recitation alone does not establish the independent historical truth of the accusation.
Practice: Why name both manners? To exclude deliberate and inadvertent killing in the required denial.