When the Tzemach Tzedek of Lubavitch zy’a was a child, he once came home from cheder and was asked by his grandfather, the Baal Hatanya zy’a, ‘What did you learn today?’
The boy answered, ‘We learned Parshas Toldos.’
The Baal Hatanya asked him, ‘What does the pasuk mean when it says (Bereishis 26:5): ‘Eikev Avrohom shama b’koli (Because Avrohom listened to My voice)?’
The child answered that it means that Avrohom Avinu heard Hashem’s commands even with the heel of his feet! (The word ‘eikev’ can mean either ‘because’ or ‘heel’.)
The Baal Hatanya enjoyed this answer very much. He said that this is also the explanation of the pasuk: ‘Vehaya eikev tishme’un.’ The entire body, down to the heel of the foot, must hear and understand the mitzvas and do them.
