It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) used to pray at night (for so long) that his (peace and blessings be upon him) blessed feet would swell. It was said to him: "O Messenger of Allah, has Allah Almighty not forgiven you all your past and future sins?" He (peace and blessings be upon him) said: "Then should I not be a grateful servant?"
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Shu'bah except Hajjaj, and Abd al-Rahman is alone in narrating it from Hajjaj."
Hadith Referenceالمعجم الأوسط / باب الجيم / 3374
Hadith Takhrij«أخرجه الطبراني فى «الصغير» برقم: 327»