His saying: "O you who are wrapped in clothing (al-Muzzammil)," means: the Prophet (peace be upon him). Al-Muzzammil is the one who is wrapped in his garments.
Muhammad said: It is said: So-and-so "tazamala" (wrapped himself) if he wrapped himself in his clothes. Everything that is wrapped is "zumila." It is reported from Ibn Abbas that he said: He says to the Prophet: "O you who are wrapped in your clothes," meaning: he puts them on for prayer.
قَوْله: ﴿يَا أَيهَا المزمل﴾ يَعْنِي: النَّبي ﷺ وَالْمُزَّمِّلُ هُوَ: المتزَمَّل بِثِيَابِهِ.
قَالَ محمدٌ: يُقَالُ: تَزَمَّلَ فلانٌ إِذَا تلفَّف بِثِيَابِهِ وَكُلُّ شيءٍ لُفِّفَ فَقَدْ زُمَّل، وَجَاءَ عَنِ ابْنِ عَبَّاسٍ أَنَّهُ قَالَ: يَقُولُ لِلنَّبِيِّ: يَا أَيُّهَا الْمُزَمِّلُ بِثِيَابِهِ يَعْنِي: يلبسهَا للصَّلَاة.