If non-Muslims (in war) say: "Saba'na'" and could not say "Aslamna'"

And Ibn 'Umar said, "Khalid started killing such infidels (thinking that they should have said *Aslamna* to be safe). The Prophet (ﷺ) ﷺ said, 'O Allah! I am free from what Khalid has done.' 'Umar said, 'If one says to another *Matras*, he is granting him security thereby. Allah knows all the tongues.' 'Umar said (to Al-Hurmuzan, a Persian leader), 'Speak, there is no harm.' (And that was taken as a sign of granting security.)