كُلٌّ فِي فَلَكٍ
Each is in an orbit.
A palindromic construction reads the same in reverse letter order. Radd al-ʿajz ʿalā al-ṣadr instead connects a terminal word with an earlier strategically placed word or cognate.
When analyzing “wa-rabbaka fa-kabbir,” distinguish the initial conjunction from the palindromic core.