So they set out, until when they came to the people of a town, they asked its people for food, but they refused to offer them hospitality. And they found therein a wall about to collapse, so he [i.e., al-Khiḍr] restored it. [Moses] said, "If you wished, you could have taken for it a payment."
Sahih International
فَٱنطَلَقَا
fa-inṭalaqā
So they set out
Word breakdown
ف
Harf · Resumption particlethen
انطلق
Fi'l · VerbSo they set out
to release, set free, divorce, set out
23× in the Quran · Rare
ا
Ism · Personal pronounthem two/their
Grammar rules
فَٱنطَلَقَا (So they set out) 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 & Presentفَٱنطَلَقَا (So they set out) uses form VII (إِنْفَعَلَ) — it's the passive or reflexive of the basic form.
We translate it as "to be [done]" or "to [verb] itself".
Lesson 13 · Verb Families V–X