Ata (may Allah have mercy on him) narrates from Sayyidah Aishah (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) used to pray four rak'ahs at night, then rest; then he (peace and blessings be upon him) would make the rak'ah so long that I would feel pity for him. I would say: May my father and mother be sacrificed for you (peace and blessings be upon him)! Allah has forgiven all your (peace and blessings be upon him) earlier and later sins! He (peace and blessings be upon him) would say: "Should I not be a grateful servant of Allah?"
Only al-Mughirah bin Ziyad narrated it, and he is not strong.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4623