Short Answer: No, believing in guardian angels is not a form of shirk, because to believe in such angels is to worship God. He tells us that he created certain angels whose responsibilities to us include guarding us, watching us, and taking down our every word and deed. There are angels who visit us and enjoy listening to our worship and reading of Quran, and there are angels who guard the entrances to Paradise and Hellfire. When a calamity strikes us, our angels have withdrawn from our protection in obedience to God, as angels do not have free will.
Peace be with you. Thank you for your question. It is very interesting.
Angels, From An Islamic Perspective
In Islam, angels accompany the children of Adam from the day they are formed in the womb until the day their soul is taken, and angels also accompany them in their graves and in the Hereafter.
The Messenger of Allah (peace and blessings be upon him) the most truthful, the most trusted, told us:
Verily the creation of any one of you takes place when he is assembled in his mother’s womb; for forty days he is a drop of fluid, then it becomes a clot for a similar period. Thereafter, it is a lump looking like it has been chewed for a similar period. Then an angel is sent to him, who breathes the ruh (spirit) into him. This angel is commanded to write four decrees: that he writes down his rizq (provision), his life span, his deeds and whether he will be among the wretched or the blessed… [Bukhari and Muslim]
Allah says there are angels responsible for guarding people throughout their lives:
For each (person), there are angels in succession, before and behind him. They guard him by the Command of God. [Qur’an 13:10]
The renowned Islamic scholar Ibn Kathir commented on Quran 13:10-11 by saying,
Each person has angels who take turns in guarding him by night and day, who protect him from evil and from accidents, just as other angels take turns in recording his deeds, good and bad, by night and by day. Two angels, on the right and the left, record his deeds. The one on the right writes down good deeds and the one on his left writes down evil deeds. Two other angels guard him and protect him, one from behind, and one from in front. So there are four angels by day and four others by night.
Our Angels Write Our Record of Deeds
Each person has been assigned two recording angels.
These angels are honourable scribes and their duty is to write down all the good and bad deeds.
Allah tells us in the Quran:
But verily, over you (are appointed angels in charge of humankind) to watch you, Kiraaman (honourable) kaatibeen – writing down (your deeds). [Quran 82:10-11]
(Remember!) that the two receivers (recording angels) receive (each human being after he or she has attained the age of puberty), one sitting on the right and one on the left (to note his or her actions). Not a word does he (or she) utter, but there is a watcher by him ready (to record it). [Qur’an 50:17-18]
Angels Who Visit Us
Apart from the four angels constantly with each human being, guarding, and recording, other angels continually visit human beings.
In his traditions, Prophet Muhammad reminds his followers that they are constantly being visited by angels.
Angels come to you in succession by night and day and all of them get together at the time of the Fajr (early morning) and Asr (afternoon) prayers. Those who have passed the night with you (or stayed with you) ascend (to the Heaven) and God asks them, though He knows everything about you well, “In what state did you leave my slaves?” The angels reply: “When we left them they were praying and when we reached them, they were praying.” [Bukhari and Muslim]
They gather to witness the prayer and listen to the recited verses of Quran.
Angels are the gatekeepers of Paradise [Qur’an 39:73] and Angels are also the gatekeepers of Hell [Quran 74:27-31].
It can therefore be understood that angels are very much involved with the life of human beings, even before and after our birth and death.
What Is Shirk?
Let us first understand “shirk”, which is: Shirk in Arabic means “taking a partner in worship.”
Shirk means ascribing to someone other than Allah something that belongs solely to Allah; a partner or rival to Allah in Lordship, divinity, or in His Names and Attributes.
For example, the Qur’an tells us:
Then do not set up rivals unto Allah (in worship) while you know (that He alone has the right to be worshipped). [Qur’an 2:22]
And of mankind are some who take (for worship) others besides Allah as rivals (to Allah). They love them as they love Allah. [Qur’an 2:165]
Shirk may take an outward or an inward form, but Shirk may also take the form of belief.
It may consist of worshipping the dead or idols, or in putting one’s complete trust in other than Allah.
Guardian Angels: Obeying Allah’s Will
Muslims only ask Allah for help and only worship Him [Qur’an 1:1-7].
Human beings and jinn are the only creations of Allah who have a free will.
Everyone and everything else only does what Allah permits them to do.
Angels do not have free will. They obey Allah’s commands without hesitation.
In other words, while the angels are protecting a person, it is by the will and permission of Allah.
If a calamity is to befall a person, the angels withdraw by the command of Allah. In other words the angels only follow the commands of Allah.
They, (angels) disobey not, the Commands they receive from God, but do that which they are commanded. [Quran 66:6]
They play a significant role in the life of a human being.
They guard and protect, record and report, and collect together with human beings who remember God.
God-Willing, this is sufficient to demonstrate the authenticity of there being angels with humans and that the angels are only following the commands of Allah.
Therefore, no question of shirk arises.
I trust this satisfactorily answers your question and please stay in touch.