"O Messenger of Allah, what do you think I should say in my supplication, if I come upon Laylatul-Qadr?" He said: "Say: 'Allahumma innaka 'afuwwun tuhibbul-'afwa, fa'fu 'anni (O Allah, You are Forgiving and love forgiveness, so forgive me).'" (Using translation from Ibn Mājah 3850)
قُلْتُ يَا رَسُولَ اللهِ إِنْ وَافَقْتُ لَيْلَةَ الْقَدْرِ فَمَا أَسْأَلُ اللهَ فِيهَا؟ قَالَ قُولِي اللهُمَّ إِنَّكَ عَفُوٌّ تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي