And they swear by Allāh their strongest oaths that if a sign came to them, they would surely believe in it. Say, "The signs are only with [i.e., from] Allāh." And what will make you perceive that even if it [i.e., a sign] came, they would not believe.
Sahih International
وَأَقْسَمُوا۟
wa-aqsamū
And they swear
Word breakdown
وَ
Harf · Resumption particleand
أَقْسَمُ
Fi'l · VerbAnd they swear
to divide, distribute; to swear, take an oath
33× in the Quran · Occasional
وا۟
Ism · Personal pronounthem/their
Grammar rules
وَأَقْسَمُوا۟ (And they swear) is a past tense verb — the action already happened and is complete.
We translate it in past tense — "did", "created", "said", etc.
Lesson 8 · Verbs — Past & Presentوَأَقْسَمُوا۟ (And they swear) 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–IV