A.T. Robertson Commentary Hebrews 10:27

"but a certain fearful expectation of judgment, and a fierceness of fire which shall devour the adversaries." — Hebrews 10:27 (ASV)

Expectation (εκδοχη). Usually reception or interpretation from εκδεχομα (Hebrews 11:10), only here in N.T. and in unusual sense like προσδοκια, like απεκδεχομα (Romans 8:19,23,25), this sense apparently "coined by the writer" (Moffatt) from his use of εκδεχομα in 10:13. The papyri have it in the sense of interpretation.

A fierceness of fire (πυρος ζηλος). An anger (zeal, jealousy) marked (genitive) by fire. Language kin to that in Isa 26:11;Zephaniah 1:19; Psalms 79:5. See also 2 Thessalonians 1:8–10 for a like picture of destined doom.

Devour (εσθιειν). "To eat" (figuratively), present active infinitive.

The adversaries (τους υπεναντιους). Old double compound adjective (υπο, εν, αντιος), in N.T. only here and Col 2:14. Those directly opposite.