MALAK AL JIBAAL
MALAK AL JIBAAL is one of the angels mentioned in the hadith. They are the angels of mountains. Believing in angels is one on the six pillars of Eeman.
One must believe that the angels are from the creation of Allah; no one knows their exact number except Him. They are from the unseen world. Allah created them to worship and obey Him. They carry out all of Allah’s orders, from administration, observation, guarding and protecting the universe as well its creatures, all according to Allah’s Will and Order.
The angels are not partners, associates, or rivals with Allah, nor are they His children; but one must still respect and love them. Allah says: "And they say: ‘The Most Beneficent (Allah) has begotten a child [from the angels].’ Far removed is He from every imperfection! They (the angels) are but honored slaves. They speak not until He has spoken, and [then] they act on His Command." Quran Surah Anbiya 21:26-27
They spend their time worshipping and obeying Allah, glorifying Him and praising Him. Allah says: "They (i.e. the angels) glorify His praises night and day, (and) without slackening (to do so)." Quran Surah Anbiya 21:20 
Narrated `Aisha: That she asked the Prophet (ﷺ) , 'Have you encountered a day harder than the day of the battle) of Uhud?" The Prophet (ﷺ) replied, "Your tribes have troubled me a lot, and the worse trouble was the trouble on the day of 'Aqaba when I presented myself to Ibn `Abd-Yalail bin `Abd-Kulal and he did not respond to my demand. So I departed, overwhelmed with excessive sorrow, and proceeded on, and could not relax till I found myself at Qarnath-Tha-alib where I lifted my head towards the sky to see a cloud shading me unexpectedly. I looked up and saw Gabriel in it. He called me saying, 'Allah has heard your people's saying to you, and what they have replied back to you, Allah has sent the Angel of the Mountains to you so that you may order him to do whatever you wish to these people.' The Angel of the Mountains called and greeted me, and then said, "O Muhammad! Order what you wish. If you like, I will let Al-Akh-Shabain (i.e. two mountains) fall on them." The Prophet (ﷺ) said, "No but I hope that Allah will let them beget children who will worship Allah Alone, and will worship None besides Him." Sahih al-Bukhari 3231 (Vol.4:454)
The angels were created from light. The Prophetﷺsaid: 'The angels were created from light, the Jinn were created from a smokeless flame of fire, and Adam was created from what was described to you (black dry clay).' Sahih Muslim 2996
A Muslim must believe specifically in all the angels named and/or described in the Qur'an and the ahadith: