Sa'id bin Jubayr said: "Had it not been for the favour of Allah upon you and His mercy" [Surah al-Nur: 20]: that is, He would have punished you for what was said about Sayyidah Aishah. "And that Allah is Most Kind": that is, Most Kind to you, since He pardoned you and did not punish you for the words of slander.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19521