أَلَا تَنْزِلُ بِنَا تُصِبْ خَيْرًا
Would you not stay with us? You would receive good.
ʿArḍ is a gentle invitation. The words alā tanzilu binā look like a question, yet they function as a polite invitation to stay. Tuṣib khayran describes the benefit contingent on accepting it.
The implied meaning is “if you stay with us, you will encounter good.” Thus an interrogative form can carry the force of an invitation and allow a dependent response.