What is this verse that is inscribed in Masjid al-Nabawī?

Have you ever looked closely at the calligraphy etched into the very walls surrounding the Prophet’s ﷺ final resting place?

This verse of poetry, visible in the Muwājahah Sharīfah* of Masjid al-Nabawī, was composed by the Qutb of Hadramawt, Yemen — Imām ʿAbdAllāh bin ʿAlawī al-Ḥaddād (d. 1132 AH). The poem, known as 𝘘𝘢𝘴̣𝘪̄𝘥𝘢 𝘢𝘭-𝘎𝘩𝘢𝘳𝘳𝘢̄ʾ (The Radiant Poem), was well received by the Ottoman Sultan of the time, who ordered that the entire poem be inscribed on the interior wall of the Prophet’s [ﷺ] Chamber (Ḥujrah).

Beside it, you can see the official Ottoman seal (tughrāʾ) in the circular medallion, dated 1228 AH (1813).

The line displayed in the exterior is the 16th verse of the qaṣīda, which reads:

نَبِيٌّ عَظِيمٌ خُلُقُهُ الْخُلُقُ الَّذِي
لَهُ عَظَّمَ الرَّحْمَٰنُ فِي سَيِّدِ الْكُتُبِ

“A great Prophet — his character is the very character
That the Most Merciful exalted in the Master of the Books.” [ﷺ]