After Allah (swt) admits the people of Paradise to Paradise, they will call out to their opponents among the kuffaar in Hell, rebuking and scolding them:

“And the dwellers of Paradise will call out to the dwellers of the Fire [saying]: “We have indeed found true what our Rabb promised us; have you also found true, what your Rabb promised [warnings, etc]? They will say “Yes”. Then a crier will proclaim between them: “The Curse of Allah is on the Dhaalimoon [wrongdoers]” [7:44]

The kuffaar used to dispute with the believers in this world, making fun of them and insulting them, but on that Day the believers will be victorious: they will be in a state of everlasting joy, looking at the wrongdoers and making fun of them:

“Verily, al-Abraar will be in delight, on thrones, looking [at all things]. You will recognize in their faces the brightness of delight. They will be given to drink pure sealed wine, the last thereof will be the smell of musk, and for this let [all] those strive who want to strive. It [that wine] will be mixed with Tasneem, a spring whereof drink those nearest to Allah. Verily [during the earthly life] those who committed crimes used to laugh at those who believed, and whenever they passed by them, used to wink to one another [in mockery]; and when they returned to their own people, they would return jesting; and when they saw them, they say, “Verily! These have indeed gone astray!” But the [disbelievers] had not been sent as watchers over them [the believers]. But this Day those who believe will laugh at the disbelievers on [high] thrones, looking [at all things]. Are not the disbelievers paid [fully] for what they used to do?” [83:22-36]

By Allah, the kuffaar will finally get the punishment that they deserve, a punishment that fits their crimes. The believer who is now in the luxury of Paradise will remember that colleague or friend who used to encourage him to follow kufr in this world and called him to embrace those misguided principles that would have placed him in the ranks of the kuffaar and enemies of Allah (swt). He will tell his companions about that former colleague, and tell them to look at him and his punishment. When he sees how he is being punished, he will realise the extent of the blessing that Allah (swt) has bestowed upon him, and how Allah (swt) has saved him from a similar fate. Then he will address his former companion and rebuke him:

“Then they will turn to one another, mutually questioning. A speaker of them will say, “Verily I had a companion [in the world] who used to say, “Are you among those who believe [in resurrection after death], [that] when we die and become dust and bones, shall we indeed [be raised up] to receive reward or punishment [according to our deeds]?” The Man said, “Will you look down?” So he looked down and saw him in the midst of the Fire. He said, “By Allah! You have nearly ruined me. Had it not been for the Grace of my Rabb, I would certainly have been among those brought forth [to Hell].” [Allah (swt) informs about the true believer that he said], “Are we not then to die [any more]? Except our first death and we shall not be punished? [after we have entered Paradise] Truly this is the supreme success! For the like of this let the workers work.” [37:50-61]