They asked it because, looking back, they could finally see what had been happening on the road. For miles they had walked with Jesus without knowing Him, because "their eyes were holden that they should not know him" (Luke 24:16). Yet something had been stirring in them the whole time He "expounded unto them in all the scriptures the things concerning himself" (Luke 24:27). Barnes says the phrase describes the deep interest and pleasure they had felt in His words before they knew who He was. Gill sees two things in the question: wonder and pleasure at what they had heard, and a kind of self-rebuke, as they seemed "to charge themselves with want of thought, with inattention and stupidity" for not recognizing Him sooner.

The question needed no spoken answer; both of them knew it was true. Their answer was to act at once: "they rose up the same hour, and returned to Jerusalem" (Luke 24:33). They found the eleven, who met them with the news, "The Lord is risen indeed, and hath appeared to Simon" (Luke 24:34). Then the two "told what things were done in the way, and how he was known of them in breaking of bread" (Luke 24:35). What had burned inside them became testimony shared with others.

Emmaus was "about threescore furlongs" from Jerusalem (Luke 24:13), which the ESV gives as about seven miles. The disciples had urged Jesus to stay because "it is toward evening, and the day is far spent" (Luke 24:29), yet they "rose up the same hour, and returned to Jerusalem" (Luke 24:33).

The Greek word for "burn" is kaiomene, a present participle ("burning") joined to "was," picturing a heart that kept on burning through the conversation. The word for "opened" is dianoigo, to open fully. Luke uses it three times in this chapter: their eyes "were opened" (Luke 24:31), He "opened to us the scriptures" (Luke 24:32), and later He "opened he their understanding" (Luke 24:45). Barnes explains "opened to us the scriptures" simply as "He explained to us the Scriptures," pointing back to Luke 24:27.

This question shows how the risen Jesus chose to make Himself known. He did not start by showing His hands or announcing His name. He began "at Moses and all the prophets" and showed from the Scriptures that the Christ ought "to have suffered these things, and to enter into his glory" (Luke 24:26-27). Only after their hearts had been warmed by the Word did He reveal Himself in the breaking of bread. Matthew Henry draws the lesson: "The expounding of those scriptures which speak of Christ has a direct tendency to warm the hearts of his disciples, both to quicken and to comfort them."

Gill links the burning to Psalm 39:3, where David says, "My heart was hot within me, while I was musing the fire burned." Barnes adds that "All the followers of Jesus know how precious and tender are the communications of the Saviour." The same pattern continues when Jesus "opened he their understanding, that they might understand the scriptures" for the whole group (Luke 24:45).