On the Day when their tongues, their hands, and their legs will bear witness against them as to what they used to do.
Ibn Abi Hatim recorded that Ibn Abbas said,
"This refers to the idolators when they realize that no one will enter Paradise except the people who used to perform Salah. They will say, `Come, let us deny (everything).' So they will deny (everything), then their mouths will be sealed and their hands and feet will testify against them, and they will not be able to hide anything from Allah."
Ibn Abi Hatim also recorded that Anas bin Malik said,
"We were with the Prophet and he smiled so broadly that his back teeth could be seen, then he said;
أَتَدْرُونَ مِمَّ أَضْحَكُ
Do you know why I am smiling?
We said, `Allah and His Messenger know best.'
He said,
مِنْ مُجَادَلَةِ الْعَبْدِ لِرَبِّهِ يَقُولُ يَا رَبِّ أَلَمْ تُجِرْنِي مِنَ الظُّلْمِ فَيَقُولُ بَلَى فَيَقُولُ لَا أُجِيزُ عَلَيَّ شَاهِدًا إِلاَّاِمنْ نَفْسِي فَيَقُولُ كَفَى بِنَفْسِكَ الْيَوْمَ عَلَيْكَ شَهِيدًا وَبِالْكِرَامِ عَلَيْكَ شُهُودًا فَيُخْتَمُ عَلَى فِيهِ وَيُقَالُ لاَِرْكَانِهِ انْطِقِي فَتَنْطِقَ بِعَمَلِهِ ثُمَّ يُخَلَّى بَيْنَهُ وَبَيْنَ الْكَلَمِ فَيَقُولُ بُعْدًا لَكُنَّ وَسُحْقًا فَعَنْكُنَّ كُنْتُ أُنَاضِلُ
Because of the way a person will dispute with his Lord. He will say, "O Lord, did you not protect me from doing wrong!"
Allah will say, "Of course,"
The person will say, "I will not accept for anyone to give testimony concerning me except myself."
Allah will say, "You are sufficient as a witness against yourself."
Then a seal will be put upon his mouth and it will be said to his faculties, "Speak." So they will speak about his deeds.
Then he will be permitted to speak, and he will say, "Away with you! I was only speaking in your defence!"
This was recorded by Muslim and An-Nasa'i