I read in the Torah that the blessing of food consists in ablution before it. So I mentioned it to the Prophet ﷺ. He said: The blessing of food consists in ablution before it and ablution after it. Sufyan disapproved of performing ablution before taking food. Abu Dawud said: It is weak.  

أَنَّ بَرَكَةَ الطَّعَامِ الْوُضُوءُ قَبْلَهُ فَذَكَرْتُ ذَلِكَ لِلنَّبِيِّ ﷺ فَقَالَ بَرَكَةُ الطَّعَامِ الْوُضُوءُ قَبْلَهُ وَالْوُضُوءُ بَعْدَهُ وَكَانَ سُفْيَانُ يَكْرَهُ الْوُضُوءَ قَبْلَ الطَّعَامِ