The inhabitants (who are Malaaikah) of the first heaven have the forms of a bull. Their commander is called Ismaaeel.
The inhabitants of the second heaven have the forms of horses. They are the army whose commander is the Angel, Dardiyaaeel. Their Tasbeeh is like thunder. Glittering Noor radiates from their mouths.
The Commander in the third heaven is Junjayaaeel. His army of Angels have the forms of birds of a great variety of colours. Every bird has 70 wings.
The Commander in the fourth heaven is Salsiyaaeel. His army of Angels have the forms of eagles. Each one has a thousand wings.
The Commander in the fifth heaven is Samkhiyaaeel. Here the Angels have the forms of small children. Each one of them is aware of seventy thousand languages (in which they recite Tasbeehaat).
The Commander in the sixth heaven is Sooryaaeel. These Angels have the form of Al-Hoorul Eeen (Damsels of Jannat). Musk emerges from their Tasbeeh.
The Commander of the seventh heaven is Beekhaaeel. His army of Angels have human forms. They perpetually seek forgiveness for Bani Aadam (i.e. human beings), and they cry when human beings die.
Some other Hadith narrations indicate other forms of Angels also inhabiting these heavens. It appears that each heaven has different forms of Malaaikah. In addition to those mentioned above, there are also Angels who have the forms of scorpions, humans, Hoor-e-Eeen (Damsels of Jannat), eagles, etc.
Above the seven heavens there is a wonderful creation called Karubi. They are constantly engaged in Tasbeeh. A Karubi dwarfs even the huge Malaaikah. He has 70,000 tongues. Each tongue recites a different Tasbeeh of Allah Azza Wa Jal. The creation of Allah Ta’ala is mind boggling and unfathomable.
In another lengthy Hadith of Rasulullah (sallallahu alayhi wasallam) narrated by Allaamah Jalaaluddin Suyuti (rahmatullah alayhi) the following description of the various classes of Malaaikah (Angels) inhabiting the different levels of the Heavens is given:
1) The first heaven (Samaa-e-Dunya) has been created a powerful solid structure. The inhabitants occupying this heaven are powerful beings having the form of cattle. Each one has wings. Some have two, some three and some four wings.
Their number equals the number of the stars. They perpetually recite Tasbeeh, Kalimah Tayyibah and Takbeer.
2) The Angels inhabiting the second heaven are as numerous as raindrops. They are in the form of scorpions. Neither do they sleep nor pause a moment in their recitation of Tasbeeh.
3) The Angels of the third heaven have human form and they are as numerous as the grains of sand. They perpetually seek refuge with Allah Ta’ala.
4) The Angels inhabiting the fourth heaven are in the form of Hoor-e-Een (Damsels of Jannat). They are as numerous as all the leaves on all the trees. They stand in rows shoulder to shoulder. Some are in Ruku’ while others are in Sajdah. Noor emanating from the Tasbeehaat which they recite permeates the heavens and the earth.
5) The Angels of the fifth heaven are twice the number of the entire animal kingdom. They have the form of eagles. They are engaged in recording divine laws. Some are supervisors of others.
6) The Angels occupying the sixth heaven have the form of beautiful horses. They are called Hizbullaah (The Army of Allah).
7) The inhabitants of the seventh heaven are the Muqarrab Angels. They enjoy a very close relationship with Allah Ta’ala. Among them are the Angels who deliver the manuscrips of deeds. Above them are the Angels who bear aloft the Divine Throne.
Above the seventh heaven is another huge, wondrous specimen of creation known as Karubi. There are many levels among them as well.