What does « To gather / To unite » mean in the Quran?

Our Lord, surely You will gather the people for a Day about which there is no doubt. Indeed, Allah does not fail in His promise."

So how will it be when We assemble them for a Day about which there is no doubt? And each soul will be compensated [in full for] what it earned, and they will not be wronged.

Those - their recompense will be that upon them is the curse of Allah and the angels and the people, all together,

And hold firmly to the rope of Allah all together and do not become divided. And remember the favor of Allah upon you - when you were enemies and He brought your hearts together and you became, by His favor, brothers. And you were on the edge of a pit of the Fire, and He saved you from it. Thus does Allah make clear to you His verses that you may be guided.

Indeed, those of you who turned back on the day the two armies met, it was Satan who caused them to slip because of some [blame] they had earned. But Allah has already forgiven them. Indeed, Allah is Forgiving and Forbearing.

And if you are killed in the cause of Allah or die - then forgiveness from Allah and mercy are better than whatever they accumulate [in this world].

And what struck you on the day the two armies met was by permission of Allah that He might make evident the [true] believers.

Those to whom hypocrites said, "Indeed, the people have gathered against you, so fear them." But it [merely] increased them in faith, and they said, "Sufficient for us is Allah, and [He is] the best Disposer of affairs."

Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives' mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.

O you who have believed, take your precaution and [either] go forth in companies or go forth all together.

Allah - there is no deity except Him. He will surely assemble you for [account on] the Day of Resurrection, about which there is no doubt. And who is more truthful than Allah in statement.

Those who take disbelievers as allies instead of the believers. Do they seek with them honor [through power]? But indeed, honor belongs to Allah entirely.

And it has already come down to you in the Book that when you hear the verses of Allah [recited], they are denied [by them] and ridiculed; so do not sit with them until they enter into another conversation. Indeed, you would then be like them. Indeed Allah will gather the hypocrites and disbelievers in Hell all together -

Never would the Messiah disdain to be a servant of Allah, nor would the angels near [to Him]. And whoever disdains His worship and is arrogant - He will gather them to Himself all together.

They have certainly disbelieved who say that Allah is Christ, the son of Mary. Say, "Then who could prevent Allah at all if He had intended to destroy Christ, the son of Mary, or his mother or everyone on the earth?" And to Allah belongs the dominion of the heavens and the earth and whatever is between them. He creates what He wills, and Allah is over all things competent.

Because of that, We decreed upon the Children of Israel that whoever kills a soul unless for a soul or for corruption [done] in the land - it is as if he had slain mankind entirely. And whoever saves one - it is as if he had saved mankind entirely. And our messengers had certainly come to them with clear proofs. Then indeed many of them, [even] after that, throughout the land, were transgressors.

Indeed, those who disbelieve - if they should have all that is in the earth and the like of it with it by which to ransom themselves from the punishment of the Day of Resurrection, it will not be accepted from them, and for them is a painful punishment

And We have revealed to you, [O Muhammad], the Book in truth, confirming that which preceded it of the Scripture and as a criterion over it. So judge between them by what Allah has revealed and do not follow their inclinations away from what has come to you of the truth. To each of you We prescribed a law and a method. Had Allah willed, He would have made you one nation [united in religion], but [He intended] to test you in what He has given you; so race to [all that is] good. To Allah is your return all together, and He will [then] inform you concerning that over which you used to differ.

O you who have believed, upon you is [responsibility for] yourselves. Those who have gone astray will not harm you when you have been guided. To Allah is you return all together; then He will inform you of what you used to do.

[Be warned of] the Day when Allah will assemble the messengers and say, "What was the response you received?" They will say, "We have no knowledge. Indeed, it is You who is Knower of the unseen"

Say, "To whom belongs whatever is in the heavens and earth?" Say, "To Allah." He has decreed upon Himself mercy. He will surely assemble you for the Day of Resurrection, about which there is no doubt. Those who will lose themselves [that Day] do not believe.

And [mention, O Muhammad], the Day We will gather them all together; then We will say to those who associated others with Allah, "Where are your 'partners' that you used to claim [with Him]?"

And if their evasion is difficult for you, then if you are able to seek a tunnel into the earth or a stairway into the sky to bring them a sign, [then do so]. But if Allah had willed, He would have united them upon guidance. So never be of the ignorant.

And [mention, O Muhammad], the Day when He will gather them together [and say], "O company of jinn, you have [misled] many of mankind." And their allies among mankind will say, "Our Lord, some of us made use of others, and we have [now] reached our term, which you appointed for us." He will say, "The Fire is your residence, wherein you will abide eternally, except for what Allah wills. Indeed, your Lord is Wise and Knowing."

Say, "With Allah is the far-reaching argument. If He had willed, He would have guided you all."