That you may warn a people whose forefathers were not warned, so they are unaware.
Sahih International
لِتُنذِرَ
litundhira
That you may warn
Word breakdown
ل
Harf · Purpose particleso that
تُنذر
Fi'l · VerbThat you may warn
to warn; a warner, warning
130× in the Quran · Common
Grammar rules
لِتُنذِرَ (That you may warn) is in the subjunctive mood — it comes after a particle like أن ("that") or لن ("will not"), which changes its ending.
We translate it as "to [verb]" or "that [someone] [verb]".
Lesson 10 · Commands & Futureلِتُنذِرَ (That you may warn) uses form IV (أَفْعَلَ) — the أ at the start makes it causative ("to make someone do something").
We translate it as "to make [someone] do" or "to cause [action]".
Lesson 12 · Verb Families II–IVلِتُنذِرَ (That you may warn) starts with لِ showing purpose — it means "so that" or "in order to".
We add "so that" or "in order to" before the verb.
Lesson 4 · Particles