Supplication on Lailatul Qadr.

Bismillahir Rahmanir Rahim
Assalamu alaikum warahmatullahi wabarakatuhu

On Lailatul Qadr - the Night of Power

Aishah (radhiya Allahu Ta'ala anha), that she said: "O Messenger of Allah! What if I knew which night Lailatul-Qadr was, then what should I say in it?" He said 'Say

اَللَّهُمَّ اِنَّكَ عَفُوٌّ ، تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي

O Allah You are The One Who pardons greatly, and loves to pardon, so pardon me.

[at Tirmidhi]