It may appear that there is no need to discuss whether angels can err or not. The obvious answer is that they are protected from wrong deeds because the liberty to commit wrong things and the weakness of omission are not extended to them. However, some commentators have a different position on the matter.
Although there is consensus that the angels who are involved in conveying the messages of Allah, particularly in communicating the same to the Prophets, are protected from all errors. A majority of scholars opine that this protection is available to all angels. However, some scholars opine that this is not a universal principle and exceptions do apply.
Allah has described the angels in high esteem at various places in the Qur’an, including the following.
“Stern angels who never disobey what He has commanded them, and always do what they are bidden.” (The Qur’an 66:6)
“(The angels respond), ‘There is not one of us without an assigned station (of worship). We are indeed the ones lined up in ranks (for Allah). And we are indeed the ones (constantly) glorifying (His praise).” (The Qur’an 37:165-166)
“And those near Him are not prevented by arrogance from His worship, nor do they tire. They exalt [Him] night and day [and] do not slacken.” (The Qur’an 21:19-20)
“Noble and dutiful.” (The Qur’an 80:16)
“Indeed, those who are near your Lord are not prevented by arrogance from His worship, and they exalt Him, and to Him they prostrate.” (The Qur’an 7:206)
“None touch it except the purified.” (The Qur’an 56:79)
The opinions of the commentators who link the high status to only specific angels who bring down messages of Allah and those who are near to Him, are based on some reports and comments found in some traditions. An analysis of such reports shows that all of them are weak. They are not sound enough to be based on giving any opinion. Most of such dissenting reports are copied from Jewish sources, which should be ignored.
Some commentators of the Qur’an refer to the two angels, Harut and Marut, who taught people magic. Obviously, those angels did not come down of their own will, but it was part of the test planned by Allah. They warned people that what they were teaching was harmful, leading to disbelief. They acted as Allah had commanded them to do so. This did not harm their status, as they remained sincere and dutiful to Allah.
Another point in support of the minority stand in this regard is that Iblis was an angel who rebelled against the command of Allah to prostrate before Adam, may Allah bestow peace on him. But the truth is that Iblis was a Jinn.
The correct position is that all the angels are protected from errors and wrong actions. They are obedient subjects of Allah, having high ranks with Him.