What is the status of «lanā fī al-dunyā ...» in explaining the verse?

Conditions of the Predicate: Ellipsis, Reconstruction and Expression

• The predicate of inna is expressed only in the first clause
• Maḥallan is the nominative predicate of the first inna
• Murtaḥalan is coordinated as the first predicate, leaving the second inna without a noun
• A relative clause