﴿ وَٱلَّذِينَ يُؤْذُونَ ٱلْمُؤْمِنِينَ وَٱلْمُؤْمِنَٰتِ بِغَيْرِ مَا ٱكْتَسَبُوا۟ فَقَدِ ٱحْتَمَلُوا۟ بُهْتَٰنًۭا وَإِثْمًۭا مُّبِينًۭا ﴾

“And as for those who malign believing men and believing women without their having done any wrong - they surely burden themselves with the guilt of calumny, and [thus] with a flagrant sin!”

(And those who malign believing men) the reference here is to Safwan (and believing women) i.e. 'A'ishah by accusing them of unchastity (undeservedly) when they are chaste, (they bear the guilt of slander and manifest sin) it is also said that this was revealed about a group of fornicators in Medina who used to harm, by their acts, the believing men and women. Allah commanded them to cease their harm and they complied.