عَنِ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَأَلَ رَجُلٌ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ عَنْ شَيْءٍ مِنْ أَمْرِ الصَّلَاةِ، فَقَالَ لَهُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: خَلِّلْ أَصَابِعَ يَدَيْكَ وَرِجْلَيْكَ، يَعْنِي إِسْبَاغَ الْوُضُوءِ، وَكَانَ فِيمَا قَالَ لَهُ: إِذَا رَكَعْتَ فَضَعْ كَفَّيْكَ عَلَى رُكْبَتَيْكَ حَتَّى تَطْمَئِنَّ (وَفِي رِوَايَةٍ حَتَّى تَطْمَئِنَّا) وَإِذَا سَجَدْتَّ فَأَمْكِنْ جَبْهَتَكَ مِنَ الْأَرْضِ حَتَّى تَجِدَ حَجْمَ الْأَرْضِ
Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) says: A man asked the Noble Prophet (peace and blessings be upon him) about a matter related to prayer, so the Prophet (peace and blessings be upon him) said to him: Clean between the fingers of your hands and feet. That is, perform ablution thoroughly. The Prophet (peace and blessings be upon him) also said to him: When you bow (in ruku‘), place your palms on your knees until they are settled in their place, then when you prostrate, place your forehead on the ground until you feel the surface of the earth.