There is not only one world in the conception of Islam, but worlds. You can call them spaces, dimensions depending on your perception and their creator, operator is Allah, God, Bog, Infinite Energy or whatever you call Him according to your culture. However, we all think about the same thing. From this vast space and the whole universe, man can comprehend only a tiny part. This is called the Visible World (A’alem al-Shihada). The rest is the Invisible World (A’alem al-Ghreib), which cannot be understood in a space considered and called as rational by man. This can only be perceived in the irrational space, if such perception develops at all. The Quran and other Scriptures help in this process. The Invisible World also has beings whom we can also perceive, get inspiration from, feel their presence. They are called angels, jinn, etc., according to different categories, but their pictorial content has been deteriorated by medieval interpretations. They are none other than beings without free will who mediate God’s ordinance. Servants, couriers, messengers, postmen, and not the least executors. The jinn are sometimes out of this line because they can be rebels too, but their punishment is never ignored. The leading figure of the angels is Jibreel, i.e. Gabriel, the messenger of Allah.

Say: Whoever is an enemy to Gabriel-for he brings down the (revelation) to thy heart by Allah's will, a confirmation of what went before, and guidance and glad tidings for those who believe, - (Quran 2:97)

In the time of Mohammed (peace be upon him) a party of Jews ridiculed the Muslims, belief that Gabriel brought down the revelations to the Prophet. They distinguished between the angels of God. For them Michael was the good who stands for them. Daniel 12:1: “At that time Michael, the great prince who protects your people, will arise. There will be a time of distress such as has not happened from the beginning of nations until then. But at that time your people—everyone whose name is found written in the book—will be delivered.” While the vision of Gabriel inspired fear. Daniel 8:16- 17: “16And I heard a man’s voice from the Ulai calling, “Gabriel, tell this man the meaning of the vision.” 17As he came near the place where I was standing, I was terrified and fell prostrate. “Son of man,” he said to me, “understand that the vision concerns the time of the end.” In this place their Book refers to the mission of Gabriel regarding his message.

Whoever is an enemy to Allah and His angels and apostles, to Gabriel and Michael, - Lo! Allah is an enemy to those who reject Faith. (Quran 2:98)

Jibreel, or Gabriel is considered the most important of all the angels in Islam. In the Quran, the angel is called Jibreel or the Holy Spirit.

Jibreel’s main responsibility is to communicate the Words of Allah to His prophets. It is Jibreel who revealed the Quran to the Prophet Muhammad (peace be upon him). But not only Mohammed, also prophets before him had relations with Jibreel.

Idris
He was the first Prophet to write with a pen. Jibreel took him to the heavens to the Angel of Death in the fourth heaven to ask how much time he had to live, and his soul was taken there and then.
Ibrahim
Jibreel appeared when Ibrahim was thrown in the fire, and asked if he could help Ibrahim, who responded that Allah (SWT) is enough for him. We learn that Jibreel always wanted to help the prophets. Jibreel also came to help Hajar, the wife of Ibrahim, tapping his heel to produce the water of Zamzam. A group of Angels also went to the house of Ibrahim to give him the glad tidings of a righteous son in his old age, and that they are there to destroy the nation of Lut.
Lut
Three angels – some accounts mention Jibraeel, Mikaeel and Israfeel – went to the town of Sodom in the guise of handsome men. The first person to see them was the daughter of Lut, who was a believer. Recognizing their beauty and fearing what would happen to them if they entered the city, she asked them to remain outside the city until Lut could safely lead them inside. He (AS) led them back to his house at night, dropping numerous hints about the corruption and evil practices of the people of the city, hoping that the travelers would change their mind about staying there. What Lut perhaps did not realize was that in dropping these hints, he was actually providing witness against his community. No community had been destroyed in the past until its Prophet had provided evidence against it.
Yusuf
As soon as Yusuf was thrown into the well by his brothers, Jibreel was standing at the bottom of the well to catch him. He caught him and comforted him. As soon as Yusuf left the protection of his father, Allah (SWT) and Jibreel became his protectors.
Zakariya
Zakariya came to Maryam asking her where she gets all her provisions from. He was given the glad tidings of a son, Yahya.
Maryam
When Maryam went to the east to contemplate and be away from the people, Jibreel came in the form of a perfect symmetrical man, whereupon she told him to fear Allah in case he had bad intentions, so he changed to his angelic form. He gave Maryam the glad tidings of Isa.
Jesus (Isa)
Jibreel raised Jesus to Allah (SWT) when the people came to kill him (4:158). In the Islam Jabreel also known as Holy spirit:

Say, the Holy Spirit has brought the revelation from thy Lord in Truth, in order to strengthen those who believe, and as a Guide and Glad Tidings to Muslims. (Quran 16:102)

The title of the Angel Gabriel, through whom the revelations came down. The People of the Book, if they had true faith, were themselves strengthened in their faith and cleared of their doubts and difficulties by the revelations brought by Al-Mustafa; and all whether People of the Book or not -who came within the fold of Islam, found the Quran a Guide and a Gospel, i.e., a substitute for the Mosaic Law and for the Christian Gospel, which had both been lost.

We gave Moses the Book and followed him up with a succession of apostles; We gave Jesus the son of Mary Clear (Signs) and strengthened him with the holy spirit. Is it that whenever there comes to you an apostle with what ye yourselves desire not, ye are puffed up with pride? - Some ye called impostors, and others ye slay! (Quran 2:87)

I omit the stories about Mohammed (peace be upon him) because of the length of the article. It is known however, that his whole life and mission are intertwined with Gabriel's ministry. For the Lord sent the ayas of Quran to the Prophet through the mediation of Gabriel for 23 years. Perhaps it comes into view that three cases are strikingly missing from the list. One is Adam, the other is Moses and the third is You, yourself. The Lord spoke directly to Adam until he was driven out of the Paradise. From then on, God sends Jibreel to the people. But once again the Lord spoke directly to Moses, without the mediation of Gabriel. By doing so, the Lord made a covenant with the children of Israel. We all know the outcome of this covenant. And at this point, let us not begin to scold the Jews, because we Muslims have committed and still commit much greater betrayal regarding our Quran. The third one to whom the Lord can speak without an intermediary is you, if you are able to call Him with the required solemnity and depths. There is only one verse in the Quran where you get authorization to do so.

When My servants ask thee concerning Me, I am indeed close (to them): I listen to the prayer of every suppliant when he calleth on Me: Let them also, with a will, Listen to My call, and believe in Me: That they may walk in the right way. (Quran 2:186)

“When my servants ask Me, I am indeed close”. The word “Say” is not here. Not like this: “When my servants ask me, say (o Mohammed), I am indeed close”. This is a unique place in Quran where Allah turns directly to the believers. And He continues: “I listen to the prayer of every servant when he calleth Me.” Also, it is a direct call for every human who believe.

Establish regular prayers - at the sun's decline till the darkness of the night, and the morning prayer and reading: for the prayer and reading in the morning carry their testimony. (Quran 17:78)

The last word “mashudan” is more than carrying a testimony. The shahid means a witness in English. Mashud thus also means that the Fajr prayers are surrounded by witnesses who are certifying it.
They testify the fulfillment of prayer, and they are touched by its depth. This depth develops between the believer and Allah.
The purpose of the above derivation is to consider Gabriel, angels, beings of the Invisible World (A’alem al-Gheib) as reality. They are there in all previous Scriptures and have the same role everywhere. The Quran states nothing else but confirms the previous statements about this. If one places him/herself in Creation in the proper way, after reaching a kind of spiritual understanding and depth, he/she will be able to perceive even the sort of reality that the eye cannot see. Moreover, he/she will be able to contact the Lord directly.
Modern societies have copied the feeling that the Church has generated, as one of its thousands of years of deception, that has been subtly applied: there is a watchful eye behind every man, a Big Brother. The church became the Big Brother instead of God. Now the secret services, technical tools you use, the supervisors of your bank account, different algorithms etc. are also an eye in the middle of your back. Angels, including Gabriel, do not fall into this category. They are the eyes on your acts and intentions that can be taken into account in the course of reckoning of the Last Judgement.