That was the turning point toward understanding in today's gospel. A companion is someone with whom we share bread. The shift is from talking about what is true to living as though something is true. And only then do things begin to fall into place. Cleopas and his friend recognized the risen Jesus when they broke bread together, when they moved from words to deeds.
Reciprocity is at the heart of the matter.
Cleopas and his friend didn't understand by listening and discussing. They understood by offering hospitality. An opening to the stranger which took a corresponding act on Jesus' part. Jesus broke the bread he had brought and they could see. And both they and the risen Jesus shared the joy.