The Essence
Az-Zaahir is the Manifest and the Ascendant. Although we cannot see Him physically, His existence is the most obvious reality in the universe, clearly proven by the intricate design and perfection of all creation.
In the Quran
وَالظَّاهِرُ وَالْبَاطِنُ ۖ وَهُوَ بِكُلِّ شَيْءٍ عَلِيمٌ
"...the Ascendant (Az-Zaahir) and the Intimate, and He is, of all things, Knowing. (Surah Al-Hadid 57:3)"
In Your Duas
وَأَنْتَ الظَّاهِرُ فَلَيْسَ فَوْقَكَ شَىْءٌ
"And You are the Manifest, there is nothing above You."
— Sahih Muslim 2713