"So it was, while they conversed and reasoned, that Jesus Himself drew near and went with them."
Good fellowship can lead to more close communion with Christ. When we are engaged in meaningful conversations--that ultimately find their focus on God--it is as if the Lord Himself wants to be a part of it. In this particular case, the disciples did not even realize that it was Christ who had drawn near to them, (see v. 16).
All of us are required, everyday, to enter into largely-mundane and almost painfully-trite interactions with people. Let us "sanctify" even these efforts, and seek to see how they might center on Jesus. This will do our souls good; and it will lead to natural and sweet evangelistic opportunities.
[Puritan quote of the day: "Though sin in a gracious soul does not die perfectly, yet it dies daily." --Thomas Watson, in his sermon, "The Beauty of Grace"]