أَهْلًا وَسَهْلًا
Translation: Welcome; literally an idiomatic expression of kinship and ease.
أَهْلًا: accusative nominal in a fixed welcoming idiom, linked to an unexpressed governing verb.
وَ: coordinating particle.
سَهْلًا: accusative expression, whose exact omitted-verb reconstruction is analyzed in different ways.
Key point: attested idioms may display an accusative without a spoken verb; do not overstate one reconstruction as unique.