وَهَدَيْنَـٰهُ ٱلنَّجْدَيْنِ
Sentence structure
وَهَدَيْنَـٰهُ is a perfect verb: attached نَا is subject and هُ the first object. ٱلنَّجْدَيْنِ is the definite dual second object.
Ayah summary
Allah showed him both the paths of good and evil.
وَهَدَيْنَـٰهُ — And shown him
Grammar: وَ coordinates; هَدَيْ is a first-person-plural perfect, attached نَا subject and هُ first object.
ٱلنَّجْدَيْنِ — the two ways
Grammar: ٱل defines the masculine dual accusative second object, marked by yā.