A.T. Robertson Commentary Hebrews 12:28

"Wherefore, receiving a kingdom that cannot be shaken, let us have grace, whereby we may offer service well-pleasing to God with reverence and awe:" — Hebrews 12:28 (ASV)

Wherefore (διο). Ground for loyalty to Christ and for calm trust in God.

That cannot be shaken (ασαλευτον). Old compound with alpha privative and the verbal adjective from σαλευω just used. In N.T. only here and Ac 27:41.

Let us have grace (εχωμεν χαριν). Present active volitive subjunctive of εχω, "Let us keep on having grace" as in 4:16, though it can mean "Let us keep on having gratitude" as in Lu 17:9.

Whereby (δι' ης). That is δια χαριτος.

We may offer service (λατρευωμεν). This subjunctive in a relative clause can be volitive like εχωμεν just before (cf. imperative στητε in 1 Peter 5:12) or it might be the futuristic subjunctive as in 8:3 (ο προσενεγκη).

Well pleasing (ευαρεστως). Old compound adverb, here only in N.T.

With reverence and awe (μετα ευλαβειας κα δεους). For ευλαβεια see 5:7; 11:7. Δεος is apprehension of danger as in a forest. "When the voice and tread of a wild beast are distinctly heard close at hand the δεος becomes φοβος" (Vincent).