Ā’ishah رَضِيَ اللهُ عَنْهَا narrated:
“I said: ‘O’ Messenger of Allāh! If I know which night Laylatul Qadr was, what should I say in it?

He صَلَّى اللّٰهُ عَلَيْهِ وَسَلَّمَ replied you should say:

‘O’ Allāh, You are The One Who pardons greatly and You love to pardon, so pardon me.’

[Saheeh ibn Mājah: 3119]