Luke 24:13-35 The Road to Emmaus
On the road to Emmaus we see two disciple of the recently deceased Jesus of Nazareth. These guys are defeated, they put all their eggs in one basket, Jesus as the Messiah, and He was killed. To add insult to injury, the body of Jesus is now missing. They have left the upper-room and were heading back home, even after the report from some in the group of angels saying that He is risen. Why?

I think they just were beyond their resources in handling all that had happened and were going back to the safety of the life they knew.
Then along comes Jesus, identity hidden from these two disciples, and offers instruction and understanding. Never being pushy He makes to go on but those disciples invite Him in. I am reminded on Revelation “I stand at the door and knock”. Finally in the breaking of the bread (the Lord’s table, Communion, the Eucharist ), revelation comes.
What I find the most interesting about this passage, at this point in my faith walk, is the disciples asking themselves, “Didn’t our hearts burn as He explained the scripture to us?” Jesus, speaking into their lives His own Word, the Living Word of God, or scripture, causes a flame to ignite in their hearts.

Jeremiah 20:7-10 The prophet and the fire
What is this fire that was ignited in the disciples? I am automatically drawn to the oft-quoted “fire shut up in my bones”. Alas, Jeremiah explains His response to the ‘reproach and derision’, or persecution of people when he speaks of the judgement of God. Even if he could stop talking about God or speaking in His name, in his heart it becomes like a burning fire shut up in his bones such that he can not endure.
In the passage from Luke we hear Jesus explain scripture, His Word, prompting a reaction from the disciples and in Jeremiah we here of what happens to the heart of the prophet when God prompts the speaking of His Word.
So what is this fire, this burning in the hearts of men at the hearing and containing of God’s Word?

Exodus 3:1-6 The burning bush
So often when we speak of a fire in the heart we think of desire or passion. A burning desire for… what? I think this is a truism but not the whole truth. Passion is that burning desire in our hearts. But then what lights that passion, what sustains that flame?
In this passage God Himself is the flame it is not the last time God presented Himself thus to Moses either. Remember in the exodus from Egypt God went before Israel in the night as a column of flame to guild and protect them. Hmmm…

Acts 2 The day of Pentecost
The promised Holy Spirit, God in us, has come, and He comes as a tongue of flame. He has come to live in our hearts to comfort and help us, to guide us in the depth of God and to help us recall everything Jesus said (See John 14,15). This same Spirit of Truth gives to us gifts (See Corinthians 11:1-11) and fruit (See Galatians 5.22,23) that all together testifies the truth of Jesus to us and those around us.
What a flame to ignite the passion in our heart! What a flame to sustain it!
I see my heart as lump of coal, dead and useless in and of itself. Once in a while match flames have come along and lit my heart up with small passions. From the desire for a leather coat to wanting a new computer or that girl walking down the street, these small desires are unsustainable and easily quenched. But what happened to our hearts when the flame-thrower of the Holy Spirit came along, when we had our own day of Pentecost? That is a flame that really sets my heart of fire, igniting a passion that is sustaining and true, purposeful and satisfying. The truth is, the flame of the Holy Spirit is the passion, being the source and sustainer of it. Without that my heart is just a lump of coal at best. At the worst my heart could be set aflame by hell and the end of that is death.