Abu Ja`far Ar-Razi (RA) reported that Ar-Rabi` bin Anas (RA) commented on this Ayah (2:26); "This is an example that Allah has given for the life of this world. The mosquito lives as long as it needs food, but when it gets fat, it dies. This is also the example of people whom Allah سبحانه وتعالى mentioned in the Qur'an: when they acquire (and collect the delights of) the life of this world, Allah سبحانه وتعالى then takes them away.'' Afterwards, he recited,
(So, when they forgot (the warning) with which they had been reminded, We opened for them the gates of every (pleasant) thing) (6:44)

In this Ayah (2:26) Allah سبحانه وتعالى stated that He does not shy away or hesitate in making an example or parable of anything, whether the example involves a significant or an insignificant matter.
Allah's سبحانه وتعالى statement,

(Or so much more when it is bigger than it) Fama fawqaha means, something bigger than the mosquito, which is one of the most insignificant and tiniest of creatures. Muslim narrated that Aishah (RA) said that the Messenger of Allah PBUH said,

(No Muslim is harmed by a thorn, Fama fawqaha (or something larger), but a good deed will be written for him and an evil deed will be erased from his record.)

So Allah سبحانه وتعالى has informed us that there is no matter that is too small that is exempt from being used as an example, even if it was as insignificant as a mosquito or a spider. Allah سبحانه وتعالى said,
(O mankind! A similitude has been coined, so listen to it (carefully): Verily, those on whom you call besides Allah, cannot create (even) a fly, even though they combine together for the purpose. And if the fly snatches away a thing from them, they will have no power to release it from the fly. So weak are (both) the seeker and the sought.) (22:73),

(The likeness of those who take (false deities as) Awliya' (protectors, helpers) other than Allah is the likeness of a spider who builds (for itself) a house; but verily, the frailest (weakest) of houses is the spider's house ـ if they but knew.) (29:41), and,

(See you not how Allah sets forth a parable A goodly word as a goodly tree, whose root is firmly fixed, and its branches (reach) to the sky (i.e. very high). Giving its fruit at all times, by the leave of its Lord, and Allah sets forth parables for mankind in order that they may remember. And the parable of an evil word is that of an evil tree uprooted from the surface of earth, having no stability. Allah will keep firm those who believe, with the word that stands firm in life of this world (i.e. they will keep on worshipping Allah alone and none else), and in the Hereafter. And Allah will cause the Zalimin (polytheists and wrongdoers) to go astray those and Allah does what He wills.) (14:24-27). Allah سبحانه وتعالى said,

(Allah سبحانه وتعالى puts forward the example of (two men ـ a believer and a disbeliever); a servant under the possession of another, he has no power of any sort) (16:75). He then said,

(And Allah سبحانه وتعالى puts forward (another) example of two men, one of them dumb, who has no power over anything, and he is a burden on his master; whichever way he directs him, he brings no good. Is such a man equal to one who commands justice) (16:76). Also, Allah سبحانه وتعالى said,

(He sets forth for you a parable from your own selves: Do you have partners among those whom your right hands possess (i.e. your servants) to share as equals in the wealth we have bestowed on you) (30:28).

(Verily, Allah is not ashamed to set forth a parable even of a mosquito or so much more when it is bigger than it.) "The believers believe in these parables, whether they involve large matters or small, because they know that they are the truth from their Lord, and Allah سبحانه وتعالى guides the believers by these parables.''

In his Tafsir, As-Suddi (RA) reported that Ibn `Abbas (RA), Ibn Mas`ud (RA)and other people among the Companions said,
(By it He misleads many), "Meaning the hypocrites. Allah سبحانه وتعالى guides the believers with these parables, and the straying of the hypocrite's increases when they reject the parables that Allah سبحانه وتعالى mentioned for them which they know are true. This is how Allah سبحانه وتعالى misleads them.''

(And He guides thereby) meaning, with the parables,

(Many) from among the people of faith and conviction, Allah سبحانه وتعالى adds guidance to their guidance, and faith to their faith, because they firmly believe in what they know to be true, that is, the parables that Allah has mentioned. This is guidance that Allah سبحانه وتعالى grants them;

(And He misleads thereby only the Fasiqin (the rebellious, disobedient to Allah سبحانه وتعالى)), meaning, the hypocrites. The Arabs say that the dates has Fasaqat, when it comes out of its skin, and they call the mouse a Fuwaysiqah, because it leaves its den to cause mischief. The Two Sahihs recorded `A'ishah (RA) saying that the Messenger of Allah PBUH said,

(Five animals are Fawasiq, and they must be killed during Ihram and otherwise: the crow, the kite, the scorpion, the mouse and the rabid dog.) eFasiq, includes the disbeliever and the disobedient. However, the Fisq of the disbeliever is worse, and this is the type of Fasiq that the Ayah is describing here, because Allah سبحانه وتعالى described them as,

(Those who break Allah's سبحانه وتعالى covenant after ratifying it, and sever what Allah سبحانه وتعالى has ordered to be joined and do mischief on earth, it is they who are the losers.)
These are the characteristics of the disbelievers and they contradict the qualities of the believers. Similarly, Allah سبحانه وتعالى said in Surat Ar-Ra`d,

(Shall he then, who knows that what has been revealed unto you (O Muhammad ) from your Lord is the truth, be like him who is blind But it is only the men of understanding that pay heed. Those who fulfill the covenant of Allah and break not the Mithaq (bond, treaty, covenant). And those who join that which Allah has commanded to be joined (i.e. they are good to their relatives and do not sever the bond of kinship), and fear their Lord, and dread the terrible reckoning.) (13:19-21)) until,

(And those who break the covenant of Allah, after its ratification, and sever that which Allah has commanded to be joined (i.e. they sever the bond of kinship and are not good to their relatives), and work mischief in the land, on them is the curse (i.e. they will be far away from Allah's mercy), and for them is the unhappy (evil) home (i.e. Hell).) (13:25)

The covenant that these deviant people broke is Allah's سبحانه وتعالى covenant with His creation, that is, to obey Him and avoid the sins that He prohibited. This covenant was reiterated in Allah's سبحانه وتعالى Books and by the words of His Messengers PBUH. Ignoring this covenant constitutes breaking it. It was said that the Ayah (2:27) is about the disbelievers and the hypocrites among the People of the Book. In this case, the covenant that they broke is the pledge that Allah سبحانه وتعالى took from them in the Tawrah to follow Muhammad PBUH when he is sent as a Prophet, and to believe in him, and in what he was sent with. Breaking Allah's سبحانه وتعالى covenant in this case occurred when the People of the Book rejected the Prophet PBUH after they knew the truth about him, and they hid this truth from people, even though they swore to Allah سبحانه وتعالى that they would do otherwise. Allah سبحانه وتعالى informed us that they threw the covenant behind their backs and sold it for a miserable price.

It was also reported that the Ayah (2:27) refers to all disbelievers, idol worshippers and hypocrites. Allah سبحانه وتعالى took their pledge to believe in His Oneness, showing them the signs that testify to His Lordship. He also took a covenant from them to obey His commands and refrain from His prohibitions, knowing that His Messengers PBUH would bring proofs and miracles that none among the creation could ever produce. These miracles testified to the truth of Allah's Messengers PBUH. The covenant was broken when the disbelievers denied what was proven to them to be authentic and rejected Allah's Prophets PBUH and Books, although they knew that they were the truth. This Tafsir was reported from Muqatil bin Hayyan (RA), and it is very good. It is also the view that Az-Zamakhshari held.
Allah's سبحانه وتعالى statement next,

(And sever what Allah has ordered to be joined) is in reference to keeping the relations with the relatives, as Qatadah asserted. This Ayah is similar to Allah's سبحانه وتعالى statement,

(Would you then, if you were given the authority, do mischief in the land, and sever your ties of kinship) (47:22)

Ibn Jarir At-Tabari (RA) preferred this opinion. However, it has been said that the meaning of the Ayah (2:27) here is more general. Hence, everything that Allah has commanded to nurture, and the people severed, is included in its meaning.