This verse quotes Deuteronomy 4.24; compare Deuteronomy 9.3; Isaiah 33.14. Our is not part of the quotation. It is not especially emphasized, as if a contrast with some other god were intended. The author rather suggests that what was said about God in the Old Testament is still true for Christians.

There is a danger in linking the clause because our God is indeed a destroying fire too closely with the preceding clause, for it might seem strange and even contradictory to “be grateful to God because he is a destroying fire.” The underlying thought may be either (a) “let us hold on to God’s promises, because he will destroy us if we are unfaithful to him”; or (b) “let us be grateful that God, who is able to destroy, has kept a permanent home for us in heaven.” Choice (a) is the meaning in the Old Testament context, and also fits in well with the writer of Hebrews’ tendency to give alternately hopeful and warning messages.

There is also a problem in the statement because our God is indeed a destroying fire, since it could be interpreted as completely identifying God with fire. This is not what is intended by the writer, and therefore it may be necessary to translate our God is indeed a destroying fire as “our God is indeed like a destroying fire” or “… a fire which destroys completely.” Destroying renders a stronger form of the verb used in its literal sense in Luke 9.54, of fire “consuming” or “destroying.” There is no suggestion here or in 10.27 of fire as a means of “refining” or “purifying.”

Quoted with permission from Ellingworth, Paul and Nida, Eugene A. A Handbook on The Letter of the Hebrews. (UBS Handbook Series). New York: UBS, 1983. For this and other handbooks for translators see here .