Read Ruku 302 of the Quran

إِنَّ ٱلَّذِينَ جَآءُو بِٱلْإِفْكِ عُصْبَةٌۭ مِّنكُمْ ۚ لَا تَحْسَبُوهُ شَرًّۭا لَّكُم ۖ بَلْ هُوَ خَيْرٌۭ لَّكُمْ ۚ لِكُلِّ ٱمْرِئٍۢ مِّنْهُم مَّا ٱكْتَسَبَ مِنَ ٱلْإِثْمِ ۚ وَٱلَّذِى تَوَلَّىٰ كِبْرَهُۥ مِنْهُمْ لَهُۥ عَذَابٌ عَظِيمٌۭ ﴿11﴾

Indeed, those who came with falsehood are a group among you. Do not think it bad for you; rather it is good for you. For every person among them is what [punishment] he has earned from the sin, and he who took upon himself the greater portion thereof - for him is a great punishment.

لَّوْلَآ إِذْ سَمِعْتُمُوهُ ظَنَّ ٱلْمُؤْمِنُونَ وَٱلْمُؤْمِنَـٰتُ بِأَنفُسِهِمْ خَيْرًۭا وَقَالُوا۟ هَـٰذَآ إِفْكٌۭ مُّبِينٌۭ ﴿12﴾

Why, when you heard it, did not the believing men and believing women think good of one another and say, "This is an obvious falsehood"?

لَّوْلَا جَآءُو عَلَيْهِ بِأَرْبَعَةِ شُهَدَآءَ ۚ فَإِذْ لَمْ يَأْتُوا۟ بِٱلشُّهَدَآءِ فَأُو۟لَـٰٓئِكَ عِندَ ٱللَّهِ هُمُ ٱلْكَـٰذِبُونَ ﴿13﴾

Why did they [who slandered] not produce for it four witnesses? And when they do not produce the witnesses, then it is they, in the sight of Allah, who are the liars.

وَلَوْلَا فَضْلُ ٱللَّهِ عَلَيْكُمْ وَرَحْمَتُهُۥ فِى ٱلدُّنْيَا وَٱلْـَٔاخِرَةِ لَمَسَّكُمْ فِى مَآ أَفَضْتُمْ فِيهِ عَذَابٌ عَظِيمٌ ﴿14﴾

And if it had not been for the favor of Allah upon you and His mercy in this world and the Hereafter, you would have been touched for that [lie] in which you were involved by a great punishment

إِذْ تَلَقَّوْنَهُۥ بِأَلْسِنَتِكُمْ وَتَقُولُونَ بِأَفْوَاهِكُم مَّا لَيْسَ لَكُم بِهِۦ عِلْمٌۭ وَتَحْسَبُونَهُۥ هَيِّنًۭا وَهُوَ عِندَ ٱللَّهِ عَظِيمٌۭ ﴿15﴾

When you received it with your tongues and said with your mouths that of which you had no knowledge and thought it was insignificant while it was, in the sight of Allah, tremendous.

وَلَوْلَآ إِذْ سَمِعْتُمُوهُ قُلْتُم مَّا يَكُونُ لَنَآ أَن نَّتَكَلَّمَ بِهَـٰذَا سُبْحَـٰنَكَ هَـٰذَا بُهْتَـٰنٌ عَظِيمٌۭ ﴿16﴾

And why, when you heard it, did you not say, "It is not for us to speak of this. Exalted are You, [O Allah]; this is a great slander"?

يَعِظُكُمُ ٱللَّهُ أَن تَعُودُوا۟ لِمِثْلِهِۦٓ أَبَدًا إِن كُنتُم مُّؤْمِنِينَ ﴿17﴾

Allah warns you against returning to the likes of this [conduct], ever, if you should be believers.

وَيُبَيِّنُ ٱللَّهُ لَكُمُ ٱلْـَٔايَـٰتِ ۚ وَٱللَّهُ عَلِيمٌ حَكِيمٌ ﴿18﴾

And Allah makes clear to you the verses, and Allah is Knowing and Wise.

إِنَّ ٱلَّذِينَ يُحِبُّونَ أَن تَشِيعَ ٱلْفَـٰحِشَةُ فِى ٱلَّذِينَ ءَامَنُوا۟ لَهُمْ عَذَابٌ أَلِيمٌۭ فِى ٱلدُّنْيَا وَٱلْـَٔاخِرَةِ ۚ وَٱللَّهُ يَعْلَمُ وَأَنتُمْ لَا تَعْلَمُونَ ﴿19﴾

Indeed, those who like that immorality should be spread [or publicized] among those who have believed will have a painful punishment in this world and the Hereafter. And Allah knows and you do not know.

وَلَوْلَا فَضْلُ ٱللَّهِ عَلَيْكُمْ وَرَحْمَتُهُۥ وَأَنَّ ٱللَّهَ رَءُوفٌۭ رَّحِيمٌۭ ﴿20﴾

And if it had not been for the favor of Allah upon you and His mercy... and because Allah is Kind and Merciful.